Customizer: Use correct panel-back icon in RTL.

props TomHarrigan.
fixes #29946.
Built from https://develop.svn.wordpress.org/trunk@29955


git-svn-id: http://core.svn.wordpress.org/trunk@29702 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add ID attribute to style element from wp_add_inline_style().

props westonruter.
fixes #30032.
Built from https://develop.svn.wordpress.org/trunk@29956


git-svn-id: http://core.svn.wordpress.org/trunk@29703 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Themes: Make "Live Preview" the primary action and "Activate" secondary.

props celloexpressions.
fixes #26899.
Built from https://develop.svn.wordpress.org/trunk@29957


git-svn-id: http://core.svn.wordpress.org/trunk@29704 1a063a9b-81f0-0310-95a4-ce76da25c4cd
wp_add_inline_style():
* Change the `wp-inline-style-$handle` class added in [29956] to `$handle-inline-css` for consistency with existing patterns.
* Add the ID attribute when concatenation is enabled as well.

props georgestephanis.
see #30032.
Built from https://develop.svn.wordpress.org/trunk@29958


git-svn-id: http://core.svn.wordpress.org/trunk@29705 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Theme install:
* Move the "based on" string below the rating to avoid wrapping to a second line.
* Reduce the gap between the theme screenshot and description.
* Fix Install button height on mobile.

props obenland, ocean90.
fixes #28148. see #29556.
Built from https://develop.svn.wordpress.org/trunk@29959


git-svn-id: http://core.svn.wordpress.org/trunk@29706 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In wp.updates.decrementCount(), only display the count if it's a valid non-negative integer.

props jdgrimes.
fixes #29527.
Built from https://develop.svn.wordpress.org/trunk@29960


git-svn-id: http://core.svn.wordpress.org/trunk@29707 1a063a9b-81f0-0310-95a4-ce76da25c4cd