Add @static* annotations where they are missing.

Initialize all static vars that are not, most to `null`.

See #32444.


git-svn-id: https://develop.svn.wordpress.org/trunk@32650 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-image-editor-gd.php

@@ -34,10 +34,12 @@ class WP_Image_Editor_GD extends WP_Image_Editor {
 	 * Checks to see if current environment supports GD.
 	 *
 	 * @since 3.5.0
+	 *
+	 * @static
 	 * @access public
 	 *
 	 * @param array $args
-	 * @return boolean
+	 * @return bool
 	 */
 	public static function test( $args = array() ) {
 		if ( ! extension_loaded('gd') || ! function_exists('gd_info') )
@@ -58,10 +60,12 @@ class WP_Image_Editor_GD extends WP_Image_Editor {
 	 * Checks to see if editor supports the mime-type specified.
 	 *
 	 * @since 3.5.0
+	 *
+	 * @static
 	 * @access public
 	 *
 	 * @param string $mime_type
-	 * @return boolean
+	 * @return bool
 	 */
 	public static function supports_mime_type( $mime_type ) {
 		$image_types = imagetypes();