Remove extra close bracket in extending.rst (#55409)

Summary:
Small typo

Pull Request resolved: https://github.com/pytorch/pytorch/pull/55409

Reviewed By: pbelevich

Differential Revision: D27611177

Pulled By: jamesr66a

fbshipit-source-id: 8a5ff702e4ab8a7eb2403432889f8b7a5a69484b
diff --git a/docs/source/notes/extending.rst b/docs/source/notes/extending.rst
index cfb7544..428b171 100644
--- a/docs/source/notes/extending.rst
+++ b/docs/source/notes/extending.rst
@@ -566,7 +566,7 @@
 
   >>> metadata = {'owner': 'Ministry of Silly Walks'}
   >>> m = MetadataTensor([[1, 2], [3, 4]], metadata=metadata)
-  >>> t = torch.tensor([[1, 2], [1, 2]]])
+  >>> t = torch.tensor([[1, 2], [1, 2]])
   >>> torch.add(t, m)
   Metadata:
   {'owner': 'Ministry of Silly Walks'}