Docs: Improve documentation for the wp_resource_hints filter.

Clarify that as of WordPress 4.7, the `$urls` parameter can accept arrays of specific HTML attributes as its child elements, in addition to URLs.

Follow-up to [37920], [38826].

Props vanyukov, Rahmohn, desrosj, peterwilsoncc, SergeyBiryukov.
Fixes #52842.

git-svn-id: https://develop.svn.wordpress.org/trunk@51048 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/general-template.php

@@ -3294,9 +3294,25 @@ function wp_resource_hints() {
 		 * Filters domains and URLs for resource hints of relation type.
 		 *
 		 * @since 4.6.0
+		 * @since 4.7.0 The `$urls` parameter accepts arrays of specific HTML attributes
+		 *              as its child elements.
 		 *
-		 * @param array  $urls          URLs to print for resource hints.
-		 * @param string $relation_type The relation type the URLs are printed for, e.g. 'preconnect' or 'prerender'.
+		 * @param array  $urls {
+		 *     Array of resources and their attributes, or URLs to print for resource hints.
+		 *
+		 *     @type array|string ...$0 {
+		 *         Array of resource attributes, or a URL string.
+		 *
+		 *         @type string $href        URL to include in resource hints. Required.
+		 *         @type string $as          How the browser should treat the resource
+		 *                                   (`script`, `style`, `image`, `document`, etc).
+		 *         @type string $crossorigin Indicates the CORS policy of the specified resource.
+		 *         @type float  $pr          Expected probability that the resource hint will be used.
+		 *         @type string $type        Type of the resource (`text/html`, `text/css`, etc).
+		 *     }
+		 * }
+		 * @param string $relation_type The relation type the URLs are printed for,
+		 *                              e.g. 'preconnect' or 'prerender'.
 		 */
 		$urls = apply_filters( 'wp_resource_hints', $urls, $relation_type );