update whatsnew

Author: jbrockmendel

doc/source/whatsnew/v1.2.0.rst

@@ -255,7 +255,7 @@ Groupby/resample/rolling
 - Bug when combining methods :meth:`DataFrame.groupby` with :meth:`DataFrame.resample` and :meth:`DataFrame.interpolate` raising an ``TypeError`` (:issue:`35325`)
 - Bug in :meth:`DataFrameGroupBy.apply` where a non-nuisance grouping column would be dropped from the output columns if another groupby method was called before ``.apply()`` (:issue:`34656`)
 - Bug in :meth:`DataFrameGroupby.apply` would drop a :class:`CategoricalIndex` when grouped on. (:issue:`35792`)
-- Bug in :meth:`DataFrameGroupby.tshift` failing to raise ``ValueError`` when a frequency cannot be inferred for the index of a group (:issue:`????`)
+- Bug in :meth:`DataFrameGroupby.tshift` failing to raise ``ValueError`` when a frequency cannot be inferred for the index of a group (:issue:`35937`)
 
 Reshaping
 ^^^^^^^^^

pandas/tests/groupby/test_allowlist.py

@@ -380,6 +380,7 @@ def test_groupby_selection_with_methods(df):
 
     # check that the index cache is cleared
     with pytest.raises(ValueError, match="Freq was not set in the index"):
+        # GH#35937
         g.tshift()
 
     # methods which aren't just .foo()