Bundled themes: Add an alt attribute with the site title for header images linked to the home page.

props rianrietveld.
fixes #15926.
Built from https://develop.svn.wordpress.org/trunk@29842


git-svn-id: http://core.svn.wordpress.org/trunk@29606 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add inline documentation for `WP_User_Query` default arguments in the form of a hash notation.

Adds documentation pointers from the class-level doc for `WP_User_Query`, as well as the `get_users()` doc.

Props tschutter.
Fixes #29846.

Built from https://develop.svn.wordpress.org/trunk@29843


git-svn-id: http://core.svn.wordpress.org/trunk@29607 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In get_terms(), select term taxonomy count for all values of 'fields'.

Not having the count caused queries with 'fields' values of 'id=>name' and
'id=>slug' to return incorrect results when querying a hierarchical taxonomy
with 'hide_empty=true'.

Includes unit tests for get_terms() when using various combinations of 'fields',
'hide_empty', and 'hierarchical' arguments.

Props technical_mastermind.
Fixes #29859.
Built from https://develop.svn.wordpress.org/trunk@29845


git-svn-id: http://core.svn.wordpress.org/trunk@29608 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add aria-describedby attributes to comment_form().

props joedolson, bramd.
fixes #24148.
Built from https://develop.svn.wordpress.org/trunk@29846


git-svn-id: http://core.svn.wordpress.org/trunk@29609 1a063a9b-81f0-0310-95a4-ce76da25c4cd