Fix typo on form_tag_helper.rb

The inline documentantion had a typo that was somewhat confusing.
Merge pull request #8719 from pcasaretto/fix-actionview-doc-typo

Fix typo on form_tag_helper.rb [ci skip]
fix env toggling, improve error page styling
Merge pull request #8713 from goshakkk/better-error-page

Fix env toggling, improve error page styling