Do not emit `prompt` as an HTML attribute when using `input_field`.

lib/simple_form/form_builder.rb

@@ -140,7 +140,7 @@ module SimpleForm
       components = (wrapper.components.map(&:namespace) & ATTRIBUTE_COMPONENTS)
 
       options = options.dup
-      options[:input_html] = options.except(:as, :boolean_style, :collection, :label_method, :value_method, *components)
+      options[:input_html] = options.except(:as, :boolean_style, :collection, :label_method, :value_method, :prompt, *components)
       options = @defaults.deep_dup.deep_merge(options) if @defaults
 
       input      = find_input(attribute_name, options)

test/form_builder/input_field_test.rb

@@ -121,6 +121,12 @@ class InputFieldTest < ActionView::TestCase
     assert_no_select 'input.boolean[boolean_style]'
   end
 
+  test 'build input_field does not treat "prompt" as a HTML attribute' do
+    with_input_field_for @user, :attempts, collection: [1,2,3,4,5], prompt: :translate
+
+    assert_no_select 'select[prompt]'
+  end
+
   test 'build input_field without pattern component use the pattern string' do
     swap_wrapper :default, custom_wrapper_with_html5_components do
       with_input_field_for @user, :name, pattern: '\w+'