Docs: Merge file-level and class-level DocBlocks in wp_get_canonical_url() test file.

Per the [https://developer.wordpress.org/coding-standards/inline-documentation-standards/php/#6-file-headers documentation standards], whenever possible, all WordPress files should contain a header DocBlock, regardless of the file’s contents – this includes files containing classes.

However, this recommendation makes less sense for unit test classes if not applied consistently, and the duplicate tags cause some confusion.

This commit aims to reduce confusion and avoid repeating information by combining the DocBlocks.

Includes using third-person singular verbs in test method descriptions, as per the documentation standards.

Follow-up to [55337], [60108], [60109].

See #63166.
Built from https://develop.svn.wordpress.org/trunk@60112


git-svn-id: http://core.svn.wordpress.org/trunk@59448 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.9-alpha-60111';
+$wp_version = '6.9-alpha-60112';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.