Add /vscode to nls fetch

A plugin may modify the root endpoint which will make /resource no
longer work so always use /vscode/resource instead.

src/browser/pages/vscode.ts

@@ -17,7 +17,7 @@ try {
       }
       // FIXME: Only works if path separators are /.
       const path = nlsConfig._resolvedLanguagePackCoreLocation + "/" + bundle.replace(/\//g, "!") + ".nls.json"
-      fetch(`${options.base}/resource/?path=${encodeURIComponent(path)}`)
+      fetch(`${options.base}/vscode/resource/?path=${encodeURIComponent(path)}`)
         .then((response) => response.json())
         .then((json) => {
           bundles[bundle] = json