Bundled Themes: Update Twenty Twenty.

This brings `trunk`’s version of Twenty Twenty in-sync with GitHub.

For a complete list of changes since [46445], see https://github.com/WordPress/twentytwenty/compare/7246fd6...bc89c51.

Props anlino, ianbelanger, poena, williampatton, nielslange, acosmin, netweb, joyously, mahesh901122, josephscott, byalextran, amolv, Clorith.
See #48110.
Built from https://develop.svn.wordpress.org/trunk@46551


git-svn-id: https://core.svn.wordpress.org/trunk@46348 1a063a9b-81f0-0310-95a4-ce76da25c4cd