Clarify that unregister_default_headers() returns void in some situations. fixes #21876.


git-svn-id: https://develop.svn.wordpress.org/trunk@27575 602fd350-edb4-49c9-b593-d223f7449a82
Heartbeat: Hooks should always receive unslashed data.

This affects the privileged hooks; the unprivileged hooks already received unslashed data.

props johnbillion, TobiasBg.
fixes #27260.


git-svn-id: https://develop.svn.wordpress.org/trunk@27576 602fd350-edb4-49c9-b593-d223f7449a82
Style the cursor in the image editor in the media modal.

props tomauger.
fixes #27392.


git-svn-id: https://develop.svn.wordpress.org/trunk@27577 602fd350-edb4-49c9-b593-d223f7449a82
TinyMCE:
- Update the styling of the image caption and gallery toolbars.
- Fix issue where the hidden clipboard div in wpView.
- Switch to using the pencil dashicon for Edit.
- Add `max-width: 100%;` to images in the gallery preview and adjust column widths.
Props cramdesign, mattheu, gcorne, melchoyce, see #27320, fixes #27376, fixes #27354


git-svn-id: https://develop.svn.wordpress.org/trunk@27578 602fd350-edb4-49c9-b593-d223f7449a82