[3.14] Docs: remove unmatched parenthesis for asyncio.TaskGroup note (GH-146035) (#146037)

Docs: remove unmatched parenthesis for `asyncio.TaskGroup` note (GH-146035)
(cherry picked from commit 4e96282)

Co-authored-by: trag1c <dev@jakubr.me>

Author: miss-islington

Doc/library/asyncio-task.rst

@@ -557,7 +557,7 @@ Running Tasks Concurrently
       provides stronger safety guarantees than *gather* for scheduling a nesting of subtasks:
       if a task (or a subtask, a task scheduled by a task)
       raises an exception, *TaskGroup* will, while *gather* will not,
-      cancel the remaining scheduled tasks).
+      cancel the remaining scheduled tasks.
 
    .. _asyncio_example_gather: