Docs: Correct parameter type documentation for various __call() methods.

See #42505


git-svn-id: https://develop.svn.wordpress.org/trunk@42151 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-oembed.php

@@ -229,7 +229,7 @@ class WP_oEmbed {
 	 *
 	 * @since 4.0.0
 	 *
-	 * @param callable $name      Method to call.
+	 * @param string   $name      Method to call.
 	 * @param array    $arguments Arguments to pass when calling.
 	 * @return mixed|bool Return value of the callback, false otherwise.
 	 */