gh-91048: Improve example in asyncio-graph.rst doc (#129224)

Author: sobolevn

Doc/library/asyncio-graph.rst

@@ -59,13 +59,13 @@ and debuggers.
 
       async def main():
           async with asyncio.TaskGroup() as g:
-              g.create_task(test())
+              g.create_task(test(), name='test')
 
       asyncio.run(main())
 
    will print::
 
-      * Task(name='Task-2', id=0x1039f0fe0)
+      * Task(name='test', id=0x1039f0fe0)
       + Call stack:
       |   File 't2.py', line 4, in async test()
       + Awaited by: