Merge pull request rails#19438 from yui-knk/fix/comment

[ci skip] Check a result of `valid?` instead of `create`

Author: Arthur Nogueira Neves

actionview/lib/action_view/helpers/form_helper.rb

@@ -69,7 +69,8 @@ module Helpers
     # controller gets a nested hash <tt>params[:person]</tt> with the person attributes
     # set in the form. That hash is ready to be passed to <tt>Person.create</tt>:
     #
-    #   if @person = Person.create(params[:person])
+    #   @person = Person.create(params[:person])
+    #   if @person.valid?
     #     # success
     #   else
     #     # error handling