Make sure .widefat border and background coloring only applies to tables. props MikeHansenMe. fixes #21936.
Verify tags used in the gallery shortcode.
Explicitly set last_changed to 1 instead of the result of wp_cache_set(). Avoids ambiguity and works with cache backends that return void instead of boolean.

see #23167
Avoid the appearance of a magic number.

Props nacin
see #23167