Docs: Correct @since version for the wp_parse_str filter.

The filter was introduced along with the `wp_parse_str()` function in WordPress 2.2.1.

Follow-up to [5709], [8662], [26485].

See #53399.

git-svn-id: https://develop.svn.wordpress.org/trunk@51609 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/formatting.php

@@ -4969,7 +4969,7 @@ function wp_parse_str( $string, &$array ) {
 	/**
 	 * Filters the array of variables derived from a parsed string.
 	 *
-	 * @since 2.3.0
+	 * @since 2.2.1
 	 *
 	 * @param array $array The array populated with variables.
 	 */