Remove most docs for ignoring_interference_by_writer

Since `ignoring_interference_by_writer` is on by default now, we don't
need to explicitly document it (unless someone wants to turn it off, but
that's unlikely).

[ci skip]

lib/shoulda/matchers/active_model/validate_absence_of_matcher.rb

@@ -70,39 +70,6 @@ module Shoulda
       #         with_message("there shall be peace on Earth")
       #     end
       #
-      # ##### ignoring_interference_by_writer
-      #
-      # Use `ignoring_interference_by_writer` when the attribute you're testing
-      # changes incoming values. This qualifier will instruct the matcher to
-      # suppress raising an AttributeValueChangedError, as long as changing the
-      # doesn't also change the outcome of the test and causes it to fail. See
-      # the documentation for `allow_value` for more information on this.
-      #
-      #     class PowerHungryCountry
-      #       include ActiveModel::Model
-      #       attr_accessor :nuclear_weapons
-      #
-      #       validates_absence_of :nuclear_weapons
-      #
-      #       def nuclear_weapons=(value)
-      #         @nuclear_weapons = value + [:hidden_weapon]
-      #       end
-      #     end
-      #
-      #     # RSpec
-      #     describe PowerHungryCountry do
-      #       it do
-      #         should validate_absence_of(:nuclear_weapons).
-      #           ignoring_interference_by_writer
-      #       end
-      #     end
-      #
-      #     # Minitest (Shoulda)
-      #     class PowerHungryCountryTest < ActiveSupport::TestCase
-      #       should validate_absence_of(:nuclear_weapons).
-      #         ignoring_interference_by_writer
-      #     end
-      #
       # @return [ValidateAbsenceOfMatcher}
       #
       def validate_absence_of(attr)

lib/shoulda/matchers/active_model/validate_acceptance_of_matcher.rb

@@ -73,39 +73,6 @@ module Shoulda
       #         with_message('You must accept the terms of service')
       #     end
       #
-      # ##### ignoring_interference_by_writer
-      #
-      # Use `ignoring_interference_by_writer` when the attribute you're testing
-      # changes incoming values. This qualifier will instruct the matcher to
-      # suppress raising an AttributeValueChangedError, as long as changing the
-      # doesn't also change the outcome of the test and cause it to fail. See
-      # the documentation for `allow_value` for more information on this.
-      #
-      #     class Registration
-      #       include ActiveModel::Model
-      #       attr_accessor :terms_of_service
-      #
-      #       validates_acceptance_of :terms_of_service
-      #
-      #       def terms_of_service=(value)
-      #         @terms_of_service = value || 'something else'
-      #       end
-      #     end
-      #
-      #     # RSpec
-      #     describe Registration do
-      #       it do
-      #         should validate_acceptance_of(:terms_of_service).
-      #           ignoring_interference_by_writer
-      #       end
-      #     end
-      #
-      #     # Minitest (Shoulda)
-      #     class RegistrationTest < ActiveSupport::TestCase
-      #       should validate_acceptance_of(:terms_of_service).
-      #         ignoring_interference_by_writer
-      #     end
-      #
       # @return [ValidateAcceptanceOfMatcher]
       #
       def validate_acceptance_of(attr)

lib/shoulda/matchers/active_model/validate_exclusion_of_matcher.rb

@@ -112,41 +112,6 @@ module Shoulda
       #         with_message('You chose a puny weapon')
       #     end
       #
-      # ##### ignoring_interference_by_writer
-      #
-      # Use `ignoring_interference_by_writer` when the attribute you're testing
-      # changes incoming values. This qualifier will instruct the matcher to
-      # suppress raising an AttributeValueChangedError, as long as changing the
-      # doesn't also change the outcome of the test and cause it to fail. See
-      # the documentation for `allow_value` for more information on this.
-      #
-      #     class Game < ActiveRecord::Base
-      #       include ActiveModel::Model
-      #       attr_accessor :weapon
-      #
-      #       validates_exclusion_of :weapon
-      #
-      #       def weapon=(value)
-      #         @weapon = value.gsub(' ', '')
-      #       end
-      #     end
-      #
-      #     # RSpec
-      #     describe Game do
-      #       it do
-      #         should validate_exclusion_of(:weapon).
-      #           in_array(['pistol', 'paintball gun', 'stick']).
-      #           ignoring_interference_by_writer
-      #       end
-      #     end
-      #
-      #     # Minitest (Shoulda)
-      #     class GameTest < ActiveSupport::TestCase
-      #       should validate_exclusion_of(:weapon).
-      #         in_array(['pistol', 'paintball gun', 'stick']).
-      #         ignoring_interference_by_writer
-      #     end
-      #
       # @return [ValidateExclusionOfMatcher]
       #
       def validate_exclusion_of(attr)

lib/shoulda/matchers/active_model/validate_inclusion_of_matcher.rb

@@ -259,42 +259,6 @@ module Shoulda
       #         allow_blank
       #     end
       #
-      # ##### ignoring_interference_by_writer
-      #
-      # Use `ignoring_interference_by_writer` when the attribute you're testing
-      # changes incoming values. This qualifier will instruct the matcher to
-      # suppress raising an AttributeValueChangedError, as long as changing the
-      # doesn't also change the outcome of the test and cause it to fail. See
-      # the documentation for `allow_value` for more information on this.
-      #
-      #     class Issue
-      #       include ActiveModel::Model
-      #       attr_accessor :state
-      #
-      #       validates_inclusion_of :state,
-      #         in: ['open', 'resolved', 'unresolved']
-      #
-      #       def state=(value)
-      #         @state = 'open'
-      #       end
-      #     end
-      #
-      #     # RSpec
-      #     describe Issue do
-      #       it do
-      #         should validate_inclusion_of(:state).
-      #           in_array(['open', 'resolved', 'unresolved']).
-      #           ignoring_interference_by_writer
-      #       end
-      #     end
-      #
-      #     # Minitest (Shoulda)
-      #     class IssueTest < ActiveSupport::TestCase
-      #       should validate_inclusion_of(:state).
-      #         in_array(['open', 'resolved', 'unresolved']).
-      #         ignoring_interference_by_writer
-      #     end
-      #
       # @return [ValidateInclusionOfMatcher]
       #
       def validate_inclusion_of(attr)

lib/shoulda/matchers/active_model/validate_length_of_matcher.rb

@@ -216,41 +216,6 @@ module Shoulda
       #         with_long_message('Secret key must be less than 100 characters')
       #     end
       #
-      # ##### ignoring_interference_by_writer
-      #
-      # Use `ignoring_interference_by_writer` when the attribute you're testing
-      # changes incoming values. This qualifier will instruct the matcher to
-      # suppress raising an AttributeValueChangedError, as long as changing the
-      # doesn't also change the outcome of the test and cause it to fail. See
-      # the documentation for `allow_value` for more information on this.
-      #
-      #     class User
-      #       include ActiveModel::Model
-      #       attr_accessor :password
-      #
-      #       validates_length_of :password, minimum: 10
-      #
-      #       def password=(value)
-      #         @password = value.upcase
-      #       end
-      #     end
-      #
-      #     # RSpec
-      #     describe User do
-      #       it do
-      #         should validate_length_of(:password).
-      #           is_at_least(10).
-      #           ignoring_interference_by_writer
-      #       end
-      #     end
-      #
-      #     # Minitest (Shoulda)
-      #     class UserTest < ActiveSupport::TestCase
-      #       should validate_length_of(:password).
-      #         is_at_least(10).
-      #         ignoring_interference_by_writer
-      #     end
-      #
       # @return [ValidateLengthOfMatcher]
       #
       def validate_length_of(attr)

lib/shoulda/matchers/active_model/validate_numericality_of_matcher.rb

@@ -296,39 +296,6 @@ module Shoulda
       #       should validate_numericality_of(:age).allow_nil
       #     end
       #
-      # ##### ignoring_interference_by_writer
-      #
-      # Use `ignoring_interference_by_writer` when the attribute you're testing
-      # changes incoming values. This qualifier will instruct the matcher to
-      # suppress raising an AttributeValueChangedError, as long as changing the
-      # doesn't also change the outcome of the test and cause it to fail. See
-      # the documentation for `allow_value` for more information on this.
-      #
-      # Here, `gpa` is an integer column, so it will typecast all values to
-      # integers. We need to use `ignoring_interference_by_writer` because the
-      # `only_integer` qualifier will attempt to set `gpa` to a float and assert
-      # that it makes the record invalid.
-      #
-      #     class Person < ActiveRecord::Base
-      #       validates_numericality_of :gpa, only_integer: true
-      #     end
-      #
-      #     # RSpec
-      #     describe Person do
-      #       it do
-      #         should validate_numericality_of(:gpa).
-      #           only_integer.
-      #           ignoring_interference_by_writer
-      #       end
-      #     end
-      #
-      #     # Minitest (Shoulda)
-      #     class PersonTest < ActiveSupport::TestCase
-      #       should validate_numericality_of(:gpa).
-      #         only_integer.
-      #         ignoring_interference_by_writer
-      #     end
-      #
       # @return [ValidateNumericalityOfMatcher]
       #
       def validate_numericality_of(attr)

lib/shoulda/matchers/active_model/validate_presence_of_matcher.rb

@@ -103,39 +103,6 @@ module Shoulda
       #         with_message('Robot has no legs')
       #     end
       #
-      # ##### ignoring_interference_by_writer
-      #
-      # Use `ignoring_interference_by_writer` when the attribute you're testing
-      # changes incoming values. This qualifier will instruct the matcher to
-      # suppress raising an AttributeValueChangedError, as long as changing the
-      # doesn't also change the outcome of the test and cause it to fail. See
-      # the documentation for `allow_value` for more information on this.
-      #
-      #     class Robot
-      #       include ActiveModel::Model
-      #       attr_accessor :name
-      #
-      #       validates_presence_of :name
-      #
-      #       def name=(name)
-      #         @name = name.to_s
-      #       end
-      #     end
-      #
-      #     # RSpec
-      #     describe Robot do
-      #       it do
-      #         should validate_presence_of(:name).
-      #           ignoring_interference_by_writer
-      #       end
-      #     end
-      #
-      #     # Minitest (Shoulda)
-      #     class RobotTest < ActiveSupport::TestCase
-      #       should validate_presence_of(:name).
-      #         ignoring_interference_by_writer
-      #     end
-      #
       # @return [ValidatePresenceOfMatcher]
       #
       def validate_presence_of(attr)