Introduce an `edit_form_before_permalink` action which gets fired after the title field but before the permalink fields. Fixes #29691. Props captaintheme

git-svn-id: https://develop.svn.wordpress.org/trunk@30028 602fd350-edb4-49c9-b593-d223f7449a82
Optimize site query when performing network database upgrades

We only use `blog_id` from the query, so we don't need a wildcard.

props marcosf
Fixes #30097


git-svn-id: https://develop.svn.wordpress.org/trunk@30029 602fd350-edb4-49c9-b593-d223f7449a82
In `wp_link_pages()`, only output link separators between actual pagination links. Fixes #24940. Props obenland.

git-svn-id: https://develop.svn.wordpress.org/trunk@30030 602fd350-edb4-49c9-b593-d223f7449a82
Improve `WP_Tax_Query` param sanitization for empty strings.

When an empty string is passed as one of the clauses in the `$tax_query`
parameter, it should be discarded rather than parsed as a first-order clause.

Props tmtrademark.
Fixes #30117.

git-svn-id: https://develop.svn.wordpress.org/trunk@30031 602fd350-edb4-49c9-b593-d223f7449a82
Cast class names to an array to avoid a potential warning.

props briandichiara
fixes #29743

git-svn-id: https://develop.svn.wordpress.org/trunk@30032 602fd350-edb4-49c9-b593-d223f7449a82