support deprecated method for HEAD support with pry-doc.

closes #1152.
related to #1136 but `? File.exists?` is still not showing me documentation.
thanks to @yui-knk for finding the bug & providing a solution.

Gemfile

@@ -1,6 +1,7 @@
 source 'https://rubygems.org'
 gemspec
 gem 'rake',  '~> 10.0'
+gem 'pry-doc'
 
 # For Guard
 group :development do

lib/pry/method.rb

@@ -148,14 +148,29 @@ class Pry
         end.flatten(1)
       end
 
+      #
       # Get all of the methods on an `Object`
+      #
       # @param [Object] obj
-      # @param [Boolean] include_super Whether to include methods from ancestors.
+      #
+      # @param [Boolean] include_super
+      #   indicates whether or not to include methods from ancestors.
+      #
       # @return [Array[Pry::Method]]
+      #
       def all_from_obj(obj, include_super=true)
         all_from_class(singleton_class_of(obj), include_super)
       end
 
+      #
+      # @deprecated
+      #  please use {#all_from_obj} instead.
+      #  the `method_type` argument is ignored.
+      #
+      def all_from_common(obj, method_type = nil, include_super=true)
+        all_from_obj(obj, include_super)
+      end
+
       # Get every `Class` and `Module`, in order, that will be checked when looking
       # for an instance method to call on this object.
       # @param [Object] obj