[New sniff] Check for the accessibility-ready tag

[carolinan]

Rule:

WARNING : Themes that use the tag accessibility-ready will need to undergo an accessibility review.

Ref: https://make.wordpress.org/themes/handbook/review/accessibility/

Theme check file covering this rule:

https://github.com/Otto42/theme-check/blob/master/checks/style_tags.php

To do:

• [ ] Create unit tests
• [ ] Create new sniff

[jrfnl]

Some notes/suggestions for implementation:

• Limit the sniff to CSS files
• At the start of the sniff check that it's reading the main style.css
• Parse the file header token, check for the tag and throw error/warning if found

[khacoder]

I have a sniff ready for this that uses the $sniff_helper array from the proposed WordPress_AbstractThemeSniff class.

[dingo-d]

I think that this check is located in the Theme Sniffer. @timelsass Is this correct?

Should this be added as a sniff, or should we let the Theme Sniffer handle this?