Allow any vimeo.com subdomain for embeds.

props danielbachhuber.
fixes #24170.


git-svn-id: https://develop.svn.wordpress.org/trunk@27225 602fd350-edb4-49c9-b593-d223f7449a82
Embolden some instructions when installing a network.

props Ipstenu.
fixes #27057.


git-svn-id: https://develop.svn.wordpress.org/trunk@27226 602fd350-edb4-49c9-b593-d223f7449a82