MAINT: improve comments, xfail messages

Author: ev-br

torch_np/_dtypes_impl.py

@@ -87,7 +87,7 @@ def nep50_to_tensors(x1, x2):
     """If either of inputs is a python scalar, type-promote with NEP 50.
 
     NB: NEP 50 mandates RuntimeWarnings on some overflows. We do not emit them:
-    we either raise OverflowError or just do the computation.
+    we either raise an OverflowError or silently do the computation.
     """
 
     x1_type, x2_type = type(x1), type(x2)

torch_np/tests/numpy_tests/core/test_scalarmath.py

@@ -495,7 +495,7 @@ def test_numpy_scalar_relational_operators(self):
                 assert_(np.array(-1, dtype=dt1)[()] == np.array(-1, dtype=dt2)[()],
                         "type %s and %s failed" % (dt1, dt2))
 
-    @pytest.mark.xfail(reason="pytorch unsigned wraps around")
+    @pytest.mark.xfail(reason="NEP50")
     def test_numpy_scalar_relational_operators_2(self):
         #Unsigned integers
         for dt1 in 'B':