Fix prose indentation [ci-skip]

Prior to this commit, the prose was formatted as a code example.

actionview/lib/action_view/helpers/text_helper.rb

@@ -261,7 +261,7 @@ def pluralize(count, singular, plural_arg = nil, plural: plural_arg, locale: I18
       #   word_wrap('Once upon a time', line_width: 1)
       #   # => Once\nupon\na\ntime
       #
-      #   You can also specify a custom +break_sequence+ ("\n" by default)
+      # You can also specify a custom +break_sequence+ ("\n" by default):
       #
       #   word_wrap('Once upon a time', line_width: 1, break_sequence: "\r\n")
       #   # => Once\r\nupon\r\na\r\ntime