update Appender to doc in datetimelike.py

Author: HH-MWB

pandas/core/indexes/datetimelike.py

@@ -157,7 +157,7 @@ def equals(self, other) -> bool:
 
         return np.array_equal(self.asi8, other.asi8)
 
-    @Appender(Index.__contains__.__doc__)
+    @doc(Index.__contains__)
     def __contains__(self, key: Any) -> bool:
         hash(key)
         try:
@@ -433,7 +433,7 @@ def _partial_date_slice(
             # try to find the dates
             return (lhs_mask & rhs_mask).nonzero()[0]
 
-    @Appender(Index.get_indexer_non_unique.__doc__)
+    @doc(Index.get_indexer_non_unique)
     def get_indexer_non_unique(self, target):
         target = ensure_index(target)
         pself, ptarget = self._maybe_promote(target)
@@ -491,7 +491,7 @@ def isin(self, values, level=None):
 
         return algorithms.isin(self.asi8, values.asi8)
 
-    @Appender(Index.where.__doc__)
+    @doc(Index.where)
     def where(self, cond, other=None):
         values = self.view("i8")
 
@@ -643,7 +643,7 @@ def _shallow_copy(self, values=None, name: Label = lib.no_default):
     # --------------------------------------------------------------------
     # Set Operation Methods
 
-    @Appender(Index.difference.__doc__)
+    @doc(Index.difference)
     def difference(self, other, sort=None):
         new_idx = super().difference(other, sort=sort)
         new_idx._set_freq(None)