Docs: Update the `@since` note for `_media_states()`.

Follow-up to [49223].

Props mukesh27.
Fixes #42063.

git-svn-id: https://develop.svn.wordpress.org/trunk@49231 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/template.php

@@ -2237,7 +2237,7 @@ function get_post_states( $post ) {
  * Outputs the attachment media states as HTML.
  *
  * @since 3.2.0
- * @since 5.6.0 Added the `$echo` parameter.
+ * @since 5.6.0 Added the `$echo` parameter and a return value.
  *
  * @param WP_Post $post The attachment post to retrieve states for.
  * @param bool    $echo Optional. Whether to echo the post states as an HTML string. Default true.