Docs: Add a missing summary and @since version to the DocBlock for _maybe_update_core().

Introduced in [10583].

See #32246.


git-svn-id: https://develop.svn.wordpress.org/trunk@35985 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/update.php

@@ -582,6 +582,10 @@ function wp_get_update_data() {
 }
 
 /**
+ * Determines whether core should be updated.
+ *
+ * @since 2.8.0
+ *
  * @global string $wp_version
  */
 function _maybe_update_core() {