Posts, Post Types: Clarify the documentation about the return value of `get_post()` when a falsey value is passed.

Props Rahe, juliobox, peterwilsoncc, hellofromTonya, audrasjb

Fixes #33068

Built from https://develop.svn.wordpress.org/trunk@50266


git-svn-id: http://core.svn.wordpress.org/trunk@49911 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/post.php

@@ -751,7 +751,9 @@ function get_extended( $post ) {
  *
  * @global WP_Post $post Global post object.
  *
- * @param int|WP_Post|null $post   Optional. Post ID or post object. Defaults to global $post.
+ * @param int|WP_Post|null $post   Optional. Post ID or post object. `null`, `false`, `0` and other PHP falsey
+ *                                 values return the current global post inside the loop. A numerically valid post
+ *                                 ID that points to a non-existent post returns `null`. Defaults to global $post.
  * @param string           $output Optional. The required return type. One of OBJECT, ARRAY_A, or ARRAY_N, which
  *                                 correspond to a WP_Post object, an associative array, or a numeric array,
  *                                 respectively. Default OBJECT.

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.7-beta1-50265';
+$wp_version = '5.7-beta1-50266';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.