Inline documentation improvements for `wp_get_playlist()`.

* Adds a missing `@param` description in the PHPDoc.
* Adds hook documentation for the `post_playlist` filter.
* Other comment cleanup.

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git-svn-id: http://core.svn.wordpress.org/trunk@27097 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Spacing fixes for code introduced in [27239].

See #26631

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git-svn-id: http://core.svn.wordpress.org/trunk@27098 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Load default settings state when creating a new playlist in the media modal. Add a few missing inline `@this` annotations in `media-editor.js`.

See #26631.


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git-svn-id: http://core.svn.wordpress.org/trunk@27099 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove a few unnecessary jQuery selectors added in [27239]. Playlists don't exist in some older contexts that galleries do.

See #26631.


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git-svn-id: http://core.svn.wordpress.org/trunk@27100 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Supply mime-type instead of extension for an item's `type` property in playlist JSON.

See #26631.


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git-svn-id: http://core.svn.wordpress.org/trunk@27101 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Get the proper image size for an item's thumb in playlist JSON.

See #26631.


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git-svn-id: http://core.svn.wordpress.org/trunk@27102 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add Oxford comma to password hint.

props trepmal.
fixes #26457.
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git-svn-id: http://core.svn.wordpress.org/trunk@27103 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix theme preview URL for themes loaded via AJAX on Install Themes screen.

props ocean90.
fixes #27128.
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git-svn-id: http://core.svn.wordpress.org/trunk@27104 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix thickbox positioning if toolbar is not present.

fixes #26745.
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git-svn-id: http://core.svn.wordpress.org/trunk@27105 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Declare $wpdb->base_prefix.

props DavidAnderson.
fixes #16762.

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git-svn-id: http://core.svn.wordpress.org/trunk@27106 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use ext/mysqli in PHP 5.5 or greater. Expect minor explosions.

props aaroncampbell, pento.
see #21663.

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git-svn-id: http://core.svn.wordpress.org/trunk@27107 1a063a9b-81f0-0310-95a4-ce76da25c4cd