[Doc] Add Tensor.Shape (#104750)

Summary:
Add `Tensor.Shape` doc.

Fix: #104038

Ref:

- https://github.com/pytorch/pytorch/issues/5544
- https://github.com/pytorch/pytorch/issues/1980

Differential Revision: D47278630

CC: @svekars @carljparker

Pull Request resolved: https://github.com/pytorch/pytorch/pull/104750
Approved by: https://github.com/mikaylagawarecki

torch/_tensor_docs.py

@@ -4727,6 +4727,26 @@ Example::
 """,
 )
 
+add_docstr_all(
+    "shape",
+    r"""
+shape() -> torch.Size
+
+Returns the size of the :attr:`self` tensor. Alias for :attr:`size`.
+
+See also :meth:`Tensor.size`.
+
+Example::
+
+    >>> t = torch.empty(3, 4, 5)
+    >>> t.size()
+    torch.Size([3, 4, 5])
+    >>> t.shape
+    torch.Size([3, 4, 5])
+
+""",
+)
+
 add_docstr_all(
     "sort",
     r"""