WP Backport Block Supports: Add text columns (column count) to typography block supports

[ramonjd]

This PR adds the PHP changes for the following Gutenberg PRs:

• Block Supports: Add text columns (column count) to typography block supports gutenberg#33587
• Style Engine: Add support for text columns (column-count) gutenberg#46566

Frontend changes also need to be ported and will be done before WP 6.3 beta (before June 27)

Testing:

npm run test:php -- --filter Tests_Theme_wpThemeJson

Trac ticket: https://core.trac.wordpress.org/ticket/58549

[ramonjd]

@aaronrobertshaw do these ported changes look okay to you?

[aaronrobertshaw]

Thank you for wrangling this backport @ramonjd

I think we might need to also backport the addition of textColumns support to the style engine which was added to Gutenberg in WordPress/gutenberg#46566. As it's all for one feature, should that be part of this backport or separate?

The changes in this PR look good in terms of addressing WordPress/gutenberg#33587 though.

[ramonjd]

I think we might need to also backport the addition of textColumns support to the style engine which was added to Gutenberg in WordPress/gutenberg#46566.

Good spotting. I'll add it to this PR. 👍

thanks

[tellthemachines]

Thanks for putting this up @ramonjd ! I spotted a missing since comment and added it in 😄

Code LGTM and in accordance with the Gutenberg PRs; it won't really be testable in the UI until npm packages are updated but I can confirm everything else in the typography support is still working correctly.

[tellthemachines]

Committed in r55985 / 9a9a672.