Fix a bug in the Item constructor parameter listHEADmaster

The id parameter of the Pagelet and Resource constructor doesn't accept
NULL values anymore (since 76cdd118d68bda3b7b29b192c7bf3d6e02bd6079).

Therefore, allow NULL values by using the parameter type "?string"
instead of "string" to allow either string values or NULL.

1 files changed, 1 insertions, 1 deletions

diff --git a/include/classes/BigPipe/Resource/Stylesheet.php b/include/classes/BigPipe/Resource/Stylesheet.php
index a5998df..9f4afba 100644
--- a/include/classes/BigPipe/Resource/Stylesheet.php
+++ b/include/classes/BigPipe/Resource/Stylesheet.php
@@ -13,7 +13,7 @@ class Stylesheet extends \BigPipe\Resource {
 	#===============================================================================
 	# Build resource
 	#===============================================================================
-	public function __construct(string $id, string $url) {
+	public function __construct(?string $id, string $url) {
 		parent::__construct($id, parent::TYPE_STYLESHEET, $url);
 	}