Docs: Document the `import_id` parameter of `wp_insert_post()`.

Follow-up to [9100].

Props donmhico.
Fixes #52943.
Built from https://develop.svn.wordpress.org/trunk@50621


git-svn-id: http://core.svn.wordpress.org/trunk@50234 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/post.php

@@ -3756,6 +3756,8 @@ function wp_get_recent_posts( $args = array(), $output = ARRAY_A ) {
  *     @type int    $menu_order            The order the post should be displayed in. Default 0.
  *     @type string $post_mime_type        The mime type of the post. Default empty.
  *     @type string $guid                  Global Unique ID for referencing the post. Default empty.
+ *     @type int    $import_id             The post ID to be used when inserting a new post.
+ *                                         If specified, must not match any existing post ID. Default 0.
  *     @type int[]  $post_category         Array of category IDs.
  *                                         Defaults to value of the 'default_category' option.
  *     @type array  $tags_input            Array of tag names, slugs, or IDs. Default empty.

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-50620';
+$wp_version = '5.8-alpha-50621';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.