Revert UI for caption fields to pre-[19982], keeping textarea for the caption...

Revert UI for caption fields to pre-[19982], keeping textarea for the caption field. No monospaced font, revert label. see #18311.



git-svn-id: https://core.svn.wordpress.org/trunk@20282 1a063a9b-81f0-0310-95a4-ce76da25c4cd