Add missing changelog entry for #8676 [ci skip]
Merge pull request #8686 from mekishizufu/changelog_entry

Add missing changelog entry for #8676 [ci skip]
Make content_tag_for work without block

This is version of #8640 for master
No need to pass a empty block to content_tag_for anymore
allow toggling dumps instead of just showing
add source line padding
Merge pull request #8689 from goshakkk/error-page

Add source code left padding on error pages
refactoring to_sym of Symbol in preload
Cleanup some unnecessary CSS on the new error page and reformat some lines.
Merge pull request #8691 from acapilleri/preload_association

refactoring to_sym of Symbol in preload
replace #flatten with Array()
Merge pull request #8692 from lucasmazza/error-page-css

Cleanup the CSS on the new error page.
Merge pull request #8693 from goshakkk/flatten

Replace #flatten with Array()
remove unnecessary #dup
Merge pull request #8688 from goshakkk/error-page-toggle

Allow toggling dumps on error page
Merge pull request #8694 from goshakkk/undup

Remove unnecessary #dup
remove another unnecessary dup
do not mutate the options hash (when we do not need to)
ask the form builder for form tag attributes
take into account multipart when calculating tag attributes