Docs: Remove @static notations from property DocBlocks in wp-admin/* and wp-includes/* classes.

This tag has been used in the past, but should no longer be used. Just using the `static` keyword in code is enough for PhpDocumentor on PHP5+ to recognize static variables and methods, and PhpDocumentor will mark them as static.

Props birgire.
See #42803.

git-svn-id: https://develop.svn.wordpress.org/trunk@42747 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-wp-screen.php

@@ -141,8 +141,6 @@ final class WP_Screen {
 	/**
 	 * Stores old string-based help.
 	 *
-	 * @static
-	 *
 	 * @var array
 	 */
 	private static $_old_compat_help = array();
@@ -160,8 +158,6 @@ final class WP_Screen {
 	 *
 	 * @since 3.3.0
 	 *
-	 * @static
-	 *
 	 * @var array
 	 */
 	private static $_registry = array();