REST API: Enable users with read_private_posts to query for them.

An authorized request with the read_private_posts capability for a post type should be able to GET /wp/v2/posts for posts of status=private. This query is further sanity-checked by WP_REST_Posts_Controller->check_read_permission(), which is unchanged.

Props rachelbaker, soulseekah, twoelevenjay.

Moves [43694] from the 5.0 branch to trunk.

Fixes #43701.

git-svn-id: https://develop.svn.wordpress.org/trunk@43979 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/rest-api.php

@@ -990,7 +990,7 @@ function rest_sanitize_boolean( $value ) {
 	}
 
 	// Everything else will map nicely to boolean.
-	return (boolean) $value;
+	return (bool) $value;
 }
 
 /**