pytester: fix docstrings

Co-Authored-By: Bruno Oliveira <[email protected]>

Author: martbln

src/_pytest/pytester.py

@@ -633,7 +633,7 @@ def copy_example(self, name=None):
         """Copy file from project's directory into the testdir.
 
         :param str name: The name of the file for copy.
-        :return: self.tmpdir
+        :return: path to the copied directory (inside ``self.tmpdir``).
 
         """
         import warnings