Bundled Themes: Update Twenty Twenty.

This brings Twenty Twenty in sync with GitHub. For a full list of changes since 5.3 RC4, see https://github.com/WordPress/twentytwenty/compare/c267289...898792b.

Props williampatton, poena, andersnoren, desrosj, schlessera, leprincenoir, alextran, aristath, b-07.
See #48110, #48386, #48450, #48505.
Fixes #48557.
Built from https://develop.svn.wordpress.org/trunk@46701


git-svn-id: https://core.svn.wordpress.org/trunk@46501 1a063a9b-81f0-0310-95a4-ce76da25c4cd