TST, DOC: add doc and test for transpose axes with negative indices (numpy#27101)

Description

This PR updates the documentation to clarify that negative indices are supported in the axes parameter of np.transpose and add test for it.

Changes made

Updated the docstring and for np.transpose to explicitly mention support for negative indices

Add test for np.transpose

Close numpy#27024

Author: guan404ming

numpy/_core/fromnumeric.py

@@ -653,10 +653,11 @@ def transpose(a, axes=None):
         Input array.
     axes : tuple or list of ints, optional
         If specified, it must be a tuple or list which contains a permutation
-        of [0,1,...,N-1] where N is the number of axes of `a`. The `i`'th axis
-        of the returned array will correspond to the axis numbered ``axes[i]``
-        of the input. If not specified, defaults to ``range(a.ndim)[::-1]``,
-        which reverses the order of the axes.
+        of [0, 1, ..., N-1] where N is the number of axes of `a`. Negative 
+        indices can also be used to specify axes. The i-th axis of the returned 
+        array will correspond to the axis numbered ``axes[i]`` of the input. 
+        If not specified, defaults to ``range(a.ndim)[::-1]``, which reverses 
+        the order of the axes.
 
     Returns
     -------
@@ -699,6 +700,10 @@ def transpose(a, axes=None):
     >>> np.transpose(a).shape
     (5, 4, 3, 2)
 
+    >>> a = np.arange(3*4*5).reshape((3, 4, 5))
+    >>> np.transpose(a, (-1, 0, -2)).shape
+    (5, 3, 4)
+
     """
     return _wrapfunc(a, 'transpose', axes)
 

numpy/_core/tests/test_numeric.py

@@ -343,6 +343,7 @@ def test_transpose(self):
         arr = [[1, 2], [3, 4], [5, 6]]
         tgt = [[1, 3, 5], [2, 4, 6]]
         assert_equal(np.transpose(arr, (1, 0)), tgt)
+        assert_equal(np.transpose(arr, (-1, -2)), tgt)
         assert_equal(np.matrix_transpose(arr), tgt)
 
     def test_var(self):