Add comment about localization string

Fixes #115781

src/vs/workbench/api/browser/mainThreadUriOpeners.ts

@@ -87,7 +87,10 @@ export class MainThreadUriOpeners extends Disposable implements MainThreadUriOpe
 
 						this.notificationService.notify({
 							severity: Severity.Error,
-							message: localize('openerFailedMessage', 'Could not open uri with \'{0}\': {1}', id, e.toString()),
+							message: localize({
+								key: 'openerFailedMessage',
+								comment: ['{0} is the id of the opener. {1} is the url being opened.'],
+							}, 'Could not open uri with \'{0}\': {1}', id, e.toString()),
 							actions: {
 								primary: [
 									openDefaultAction