Invalid value for speak CSS property

[Hareesh Pillai]

Follow up to #51587

Core has some CSS files that contain the speak CSS property with a value of none.

This is not a valid value for the speak CSS property. never is the correct value.

[SergeyBiryukov]

Thanks for the patch! It looks like there are some changes for external packages:

• Thickbox: This appears to not be maintained upstream and had quite a few fixes in core over the years already, so should be fine to patch.
• Genericons in Twenty Fifteen: This appears to be maintained at ​https://github.com/Automattic/Genericons, but there is no activity for the last four years, so it's probably OK to patch here. That said, a PR should be created for the same change upstream too.
• Genericons in Twenty Sixteen: Same as above.

[SergeyBiryukov]

In 49309:

General: Use correct value for the speak property in various CSS files.

Follow-up to [49263].

Props hareesh-pillai.
Fixes #51622.

[SergeyBiryukov]

Replying to SergeyBiryukov:

Genericons in Twenty Fifteen: This appears to be maintained at ​https://github.com/Automattic/Genericons, but there is no activity for the last four years, so it's probably OK to patch here. That said, a PR should be created for the same change upstream too.

For reference, this was done in ​https://github.com/Automattic/Genericons/pull/112. Thanks @hareesh-pillai!