About page updates.
 * Live-update the number of active translations.
 * Finalize most strings.
 * Lazily remove links to admin-only screens based on cap checks.
see #30435.

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git-svn-id: http://core.svn.wordpress.org/trunk@30830 1a063a9b-81f0-0310-95a4-ce76da25c4cd