Customizer: Prevent double-encoding in `WP_Customize_Control`.

Control's label and description may include HTML.

fixes #29572.
Built from https://develop.svn.wordpress.org/trunk@30326


git-svn-id: http://core.svn.wordpress.org/trunk@30325 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Improve keyboard accessibility on Custom Header and Custom Background screen.

props florianziegler.
fixes #29289.
Built from https://develop.svn.wordpress.org/trunk@30327


git-svn-id: http://core.svn.wordpress.org/trunk@30326 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Correct `@since` tag in `count_user_posts()` docs.

Props pavelevap, DrewAPicture.
See #21364.
Built from https://develop.svn.wordpress.org/trunk@30328


git-svn-id: http://core.svn.wordpress.org/trunk@30327 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Customizer: Improve ability to filter active state for widget area Customizer sections.

* Mark panels, sections, controls as active if preview explicitly indicates.
* Introduce `WP_Customize_Sidebar_Section` PHP class, and `SidebarSection` JS class.
* Move logic for determining whether a sidebar section is active from the `SidebarControl` to `SidebarSection`.

props westonruter.
fixes #30235.
Built from https://develop.svn.wordpress.org/trunk@30329


git-svn-id: http://core.svn.wordpress.org/trunk@30328 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Color Picker: Allow to override `mode` and `width` values for Iris via wpColorPicker options.

props jtsternberg.
fixes #30182.
Built from https://develop.svn.wordpress.org/trunk@30330


git-svn-id: http://core.svn.wordpress.org/trunk@30329 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fifteen: Add a transparent border to a link in the footer to avoid jumpiness on hover.

props iamtakashi.
fixes #30332.
Built from https://develop.svn.wordpress.org/trunk@30331


git-svn-id: http://core.svn.wordpress.org/trunk@30330 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix selector for the "Live Widget Previews" feature pointer.

props rzen.
fixes #30158.
Built from https://develop.svn.wordpress.org/trunk@30332


git-svn-id: http://core.svn.wordpress.org/trunk@30331 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Introduce a button on the user profile screen which clears all other sessions, and on the user editing screen which clears all sessions. Only appears when there are applicable sessions which can be cleared.

See #30264.
Props jorbin, ocean90, johnbillion


Built from https://develop.svn.wordpress.org/trunk@30333


git-svn-id: http://core.svn.wordpress.org/trunk@30332 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Improvements to [30333]:

* Move `.hide-if-no-js` class to table row
* Add a wrapper class
* Add missing translators comment

see #30264.
Built from https://develop.svn.wordpress.org/trunk@30334


git-svn-id: http://core.svn.wordpress.org/trunk@30333 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Site Language: Install translations on the fly.

The language dropdown now includes installed languages and all available translations when the filesystem is writable by WordPress.
Go to wp-admin/options-general.php, select one of the available translations, submit the form and let WordPress handle the rest.
Works for Multisite's Default Language too.

see #29395.
Built from https://develop.svn.wordpress.org/trunk@30335


git-svn-id: http://core.svn.wordpress.org/trunk@30334 1a063a9b-81f0-0310-95a4-ce76da25c4cd