Update the error message in test_indexing.py

Author: natmokval

pandas/tests/indexes/numeric/test_indexing.py

@@ -600,7 +600,7 @@ def test_slice_locs_na(self):
 
     def test_slice_locs_na_raises(self):
         index = Index([np.nan, 1, 2])
-        msg = "non-monotonic index with a non-specific label: 1.5"
+        msg = "non-monotonic index with a missing label 1.5"
         with pytest.raises(KeyError, match=msg):
             index.slice_locs(start=1.5)