web: fix declaration of Intl

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

web/src/global.d.ts

@@ -1 +1,8 @@
 declare module "*.css";
+
+declare namespace Intl {
+    class ListFormat {
+        constructor(locale: string, args: { [key: string]: string });
+        public format: (items: string[]) => string;
+    }
+}