Docs: Fix @param type for get_posts().

The `$args` parameter is passed through `wp_parse_args()`, which accepts both arrays and query strings. Update the `@param` type from `array` to `array|string` to reflect this, consistent with other functions like `wp_list_categories()` and `get_terms()`.

Author: rodrigoprimo

src/wp-includes/post.php

@@ -2599,7 +2599,7 @@ function is_post_embeddable( $post = null ) {
  * @see WP_Query
  * @see WP_Query::parse_query()
  *
- * @param array $args {
+ * @param array|string $args {
  *     Optional. Arguments to retrieve posts. See WP_Query::parse_query() for all available arguments.
  *
  *     @type int        $numberposts      Total number of posts to retrieve. Is an alias of `$posts_per_page`