Narrow return type declaration

The called method UrlGenerator::canonicalUrl() never returns null.

Author: greg0ire

packages/guides/src/RenderContext.php

@@ -94,7 +94,7 @@ public function getLink(string $name, bool $relative = true): string
         return '';
     }
 
-    public function canonicalUrl(string $url): string|null
+    public function canonicalUrl(string $url): string
     {
         return $this->urlGenerator->canonicalUrl($this->getDirName(), $url);
     }