Fixes #14677: No discoverable way to turn off a task in vscode once its started.

src/vs/workbench/parts/tasks/electron-browser/task.contribution.ts

@@ -830,7 +830,7 @@ class TaskService extends EventEmitter implements ITaskService {
 						if (executeResult.kind === TaskExecuteKind.Active) {
 							let active = executeResult.active;
 							if (active.same && active.watching) {
-								this.messageService.show(Severity.Info, nls.localize('TaskSystem.activeSame', 'The task is already active and in watch mode.'));
+								this.messageService.show(Severity.Info, nls.localize('TaskSystem.activeSame', 'The task is already active and in watch mode. To terminate the task use `F1 > terminate task`'));
 							} else {
 								throw new TaskError(Severity.Warning, nls.localize('TaskSystem.active', 'There is an active running task right now. Terminate it first before executing another task.'), TaskErrors.RunningTask);
 							}