Make the list of gallery attachments in the "old iframe media modal" break less. The "columns" are not aligned with the headers, but this would require a markup rewrite of a deprecated feature.

Fixes #28098.


Built from https://develop.svn.wordpress.org/trunk@28829


git-svn-id: http://core.svn.wordpress.org/trunk@28633 1a063a9b-81f0-0310-95a4-ce76da25c4cd
The "old iframe media modal" has some pretty busted styles. Although this is a "deprecated" feature, clean up some of the broken styles.

Props erayalakese for the JS patch.
Fixes #28220.


Built from https://develop.svn.wordpress.org/trunk@28830


git-svn-id: http://core.svn.wordpress.org/trunk@28634 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Optimize the `wptexturize()` loop:
* Take the ampersand pattern out of the loop for speed.
* Fix old bugs in the ampersand pattern.
* Refactor `_wptexturize_pushpop_element()` without PCRE for speed.
* Update unit tests.

Props miqrogroove.
Fixes #28623.

Built from https://develop.svn.wordpress.org/trunk@28831


git-svn-id: http://core.svn.wordpress.org/trunk@28635 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Bring the list of `upload_filetypes` for multisite into modernity based on .com upgrades and supported extensions for audio and video.

Fixes #24434.

Built from https://develop.svn.wordpress.org/trunk@28832


git-svn-id: http://core.svn.wordpress.org/trunk@28636 1a063a9b-81f0-0310-95a4-ce76da25c4cd