About: Add vertical alignment for developer happiness sections.

Also run CSS autoprefixer to add `-ms-` prefixes for CSS grid identifiers for IE11.

Props Presskopp.
Amends [42121].
See #42087.
Fixes #42524 for trunk.

Built from https://develop.svn.wordpress.org/trunk@42161


git-svn-id: https://core.svn.wordpress.org/trunk@41992 1a063a9b-81f0-0310-95a4-ce76da25c4cd