Add screen reader text for star ratings on Install Plugins screen.

props joedolson.
fixes #28852.
Built from https://develop.svn.wordpress.org/trunk@29232


git-svn-id: http://core.svn.wordpress.org/trunk@29016 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Reverse the order of roles in help text on Add New User screen to match [25695].

fixes #28914.
Built from https://develop.svn.wordpress.org/trunk@29233


git-svn-id: http://core.svn.wordpress.org/trunk@29017 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use an existing string.

see #19205.
Built from https://develop.svn.wordpress.org/trunk@29234


git-svn-id: http://core.svn.wordpress.org/trunk@29018 1a063a9b-81f0-0310-95a4-ce76da25c4cd