Docs: Miscellaneous inline documentation improvements, including:

* Document the post statuses global as an array of `stdClass` objects
* Document the taxonomies global as an array of `WP_Taxonomy` objects
* Document the return value of the post count functions as `stdClass` objects
* Fix some typos

See #53399


git-svn-id: https://develop.svn.wordpress.org/trunk@51885 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/functions.php

@@ -1533,7 +1533,7 @@ function get_num_queries() {
  * @since 1.0.0
  *
  * @param string $yn Character string containing either 'y' (yes) or 'n' (no).
- * @return bool True if yes, false on anything else.
+ * @return bool True if 'y', false on anything else.
  */
 function bool_from_yn( $yn ) {
 	return ( 'y' === strtolower( $yn ) );