Change header underline etc.

Author: topper-123

doc/source/getting_started/basics.rst

@@ -1525,7 +1525,7 @@ To iterate over the rows of a DataFrame, you can use the following methods:
     df
 
 items
-~~~~~~~~~
+~~~~~
 
 Consistent with the dict-like interface, :meth:`~DataFrame.items` iterates
 through key-value pairs:

pandas/core/generic.py

@@ -1940,6 +1940,10 @@ def items(self):
         """Iterate over (label, values) on info axis
 
         This is index for Series and columns for DataFrame.
+
+        Returns
+        -------
+        Generator
         """
         for h in self._info_axis:
             yield h, self[h]