DOC: fix code in groupby documentation (#50640)

* DOC: fix code in  groupby documentation

* fix typo in docstring

Author: abonte

doc/source/user_guide/groupby.rst

@@ -1083,6 +1083,7 @@ The dimension of the returned result can also change:
     def f(group):
         return pd.DataFrame({'original': group,
                              'demeaned': group - group.mean()})
+
     grouped.apply(f)
 
 ``apply`` on a Series can operate on a returned value from the applied function,

pandas/core/arrays/datetimes.py

@@ -1678,7 +1678,7 @@ def isocalendar(self) -> DataFrame:
         See Also
         --------
         quarter : Return the quarter of the date.
-        is_quarter_end : Similar property for indicating the quarter start.
+        is_quarter_end : Similar property for indicating the quarter end.
 
         Examples
         --------