DOC: Update the DatetimeIndex.normalize docstring (#20094)

Author: techytushar

pandas/core/indexes/datetimes.py

@@ -1964,11 +1964,41 @@ def date(self):
 
     def normalize(self):
         """
-        Return DatetimeIndex with times to midnight. Length is unaltered
+        Convert times to midnight.
+
+        The time component of the date-timeise converted to midnight i.e.
+        00:00:00. This is useful in cases, when the time does not matter.
+        Length is unaltered. The timezones are unaffected.
+
+        This method is available on Series with datetime values under
+        the ``.dt`` accessor, and directly on DatetimeIndex.
 
         Returns
         -------
-        normalized : DatetimeIndex
+        DatetimeIndex or Series
+            The same type as the original data. Series will have the same
+            name and index. DatetimeIndex will have the same name.
+
+        See Also
+        --------
+        floor : Floor the datetimes to the specified freq.
+        ceil : Ceil the datetimes to the specified freq.
+        round : Round the datetimes to the specified freq.
+
+        Examples
+        --------
+        >>> idx = pd.DatetimeIndex(start='2014-08-01 10:00', freq='H',
+        ...                        periods=3, tz='Asia/Calcutta')
+        >>> idx
+        DatetimeIndex(['2014-08-01 10:00:00+05:30',
+                       '2014-08-01 11:00:00+05:30',
+                       '2014-08-01 12:00:00+05:30'],
+                        dtype='datetime64[ns, Asia/Calcutta]', freq='H')
+        >>> idx.normalize()
+        DatetimeIndex(['2014-08-01 00:00:00+05:30',
+                       '2014-08-01 00:00:00+05:30',
+                       '2014-08-01 00:00:00+05:30'],
+                       dtype='datetime64[ns, Asia/Calcutta]', freq=None)
         """
         new_values = conversion.date_normalize(self.asi8, self.tz)
         return DatetimeIndex(new_values, freq='infer', name=self.name,