add comment to explain rewriteDownloadUrls

Author: artlowel

src/environments/environment.common.ts

@@ -216,5 +216,6 @@ export const environment: GlobalConfig = {
   theme: {
     name: 'default',
   },
+  // Whether the UI should rewrite file download URLs to match its domain. Only necessary to enable when running UI and REST API on separate domains
   rewriteDownloadUrls: false,
 };