Localize error message for comment thread add failure

src/vs/workbench/contrib/comments/electron-browser/commentsEditorContribution.ts

@@ -602,7 +602,7 @@ export class ReviewController implements IEditorContribution {
 						this.processNextThreadToAdd();
 					})
 					.catch(e => {
-						this.notificationService.error(`Adding a new comment thread failed: ${e}`);
+						this.notificationService.error(nls.localize('commentThreadAddFailure', "Adding a new comment thread failed failed: {0}.", e.message));
 						this.processNextThreadToAdd();
 					});
 			}