Add a note stating that iteration is defined for 1-D arrays not other arrays

Fixes #818.

Author: asmeurer

src/array_api_stubs/_draft/array_object.py

@@ -629,6 +629,10 @@ def __getitem__(
         -------
         out: array
             an array containing the accessed value(s). The returned array must have the same data type as ``self``.
+
+        .. note::
+           When ``__getitem__`` is defined on an object, Python will automatically define iteration (i.e., the behavior from ``iter(x)``) as  ``x[0]``, ``x[1]``, .... This can also be implemented directly by defining ``__iter__``. Therefore, for 1-D arrays, iteration should produce the sequence ``x[0]``, ``x[1]``, ... of 0-D arrays. Iteration behavior for arrays with more than one dimension is unspecified and thus implementation-defined.
+
         """
 
     def __gt__(self: array, other: Union[int, float, array], /) -> array: