Post review improvements.

Reviewed by Marco.

Author: samuelsinayoko

pandas/core/frame.py

@@ -5250,13 +5250,14 @@ def stack(self, level=-1, dropna=True):
 
         Returns
         -------
-        stacked : DataFrame or Series
+        DataFrame or Series
+            Stacked dataframe or series.
 
         See Also
         --------
-        pandas.DataFrame.unstack: unstack prescribed level(s) from index axis onto column axis.
-        pandas.DataFrame.pivot: reshape dataframe from long format to wide format.
-        pandas.DataFrame.pivot_table: create a spreadsheet-style pivot table as a DataFrame.
+        DataFrame.unstack: unstack prescribed level(s) from index axis onto column axis.
+        DataFrame.pivot: reshape dataframe from long format to wide format.
+        DataFrame.pivot_table: create a spreadsheet-style pivot table as a DataFrame.
         """
         from pandas.core.reshape.reshape import stack, stack_multiple