debug: fix wording

fixes #29900

src/vs/workbench/parts/debug/electron-browser/debugService.ts

@@ -863,7 +863,7 @@ export class DebugService implements debug.IDebugService {
 
 			if (this.lastTaskEvent) {
 				// there is a different task running currently.
-				return TPromise.wrapError(errors.create(nls.localize('differentTaskRunning', "There is a task {0} running. Can not run pre launch task {1}.", this.lastTaskEvent.taskName, taskName)));
+				return TPromise.wrapError(errors.create(nls.localize('differentTaskRunning', "The task '{0}' is already running. Cannot run pre-launch task '{1}'.", this.lastTaskEvent.taskName, taskName)));
 			}
 
 			// no task running, execute the preLaunchTask.