Update/add plugin recommendation strings.

Update [30887], add a translation function to the Vine string.

Merges [30889] to the 4.1 branch.

Fixes #30337.

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git-svn-id: http://core.svn.wordpress.org/branches/4.1@30888 1a063a9b-81f0-0310-95a4-ce76da25c4cd