Check bad dates and redirect, instead of 404ing, as necessary and appropriate. 
Adds query, conditional, and canonical Unit Tests.

Props kovshenin, SergeyBiryukov, DrewAPicture.
Fixes #10935.


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Inline documentation for hooks in xmlrpc.php.

The old link for RSD is dead; update to the new one.

props bftrick.
see #25229.

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Document comment_edit_redirect.

props dustyf.
see #25229.

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Mark the hooks in custom-background.php as duplicates.
 * image_size_names_choose should be documented in wp-includes/media.php
 * wp_create_file_in_uploads should be documented in custom-header.php

see #25229.

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Document the 'query' filter in wp-db.

props natejacobs.
see #25229.

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Use `get_the_title()` when dealing with `post_type`-like items in the admin. 

Props nacin, DrewAPicture.
Fixes #14975.


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Inline docs for hooks in MagPie.

props natejacobs.
see #25229.

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Allow `is_tag()` to accept `term_id`, `slug`, 'term_name` or array of any. Many other `is_*()` funcs already do this. Adds unit tests.

Props ramiy.
Fixes #18746.


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Correct @since in admin-footer. see #25229.

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Introduce `wp_using_ext_object_cache()` - mimic `wp_suspend_cache_invalidation()` and discourage direct access to `$_wp_using_ext_object_cache`, cleaning up importing of globals in functions and provides function to modify that global.  Loads the packaged object cache when an external cache hasn't been loaded or doesn't contain `wp_cache_init()`.

Fixes #21401.


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