new clang warning fix (#3132)

Author: mikea

src/workerd/jsg/url.h

@@ -372,4 +372,4 @@ class UrlPattern final {
 
 // Append _url to a string literal to create a parsed URL. An assert will be triggered
 // if the value cannot be parsed successfully.
-const workerd::jsg::Url operator"" _url(const char* str, size_t size) KJ_WARN_UNUSED_RESULT;
+const workerd::jsg::Url operator""_url(const char* str, size_t size) KJ_WARN_UNUSED_RESULT;