Docs: Mark apply_filters() third parameter $args as optional.

The `$args` parameter of `apply_filters()` is optional. This changeset updates the related Docblock description accordingly so the parameter is not marked as 
`required` on DevHub.

Props gaeldenysiak, audrasjb, gilles66.
Fixes #58481.
See #57840.


Built from https://develop.svn.wordpress.org/trunk@55893


git-svn-id: http://core.svn.wordpress.org/trunk@55405 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/plugin.php

@@ -167,7 +167,7 @@ function add_filter( $hook_name, $callback, $priority = 10, $accepted_args = 1 )
  *
  * @param string $hook_name The name of the filter hook.
  * @param mixed  $value     The value to filter.
- * @param mixed  ...$args   Additional parameters to pass to the callback functions.
+ * @param mixed  ...$args   Optional. Additional parameters to pass to the callback functions.
  * @return mixed The filtered value after all hooked functions are applied to it.
  */
 function apply_filters( $hook_name, $value, ...$args ) {