#14649: clarify DocTestSuite error when there are no docstrings.

Also adds tests to verify the documented behavior (which is probably a bug, as
indicated in the added comments).

Patch by Chris Jerdonek.

Lib/test/sample_doctest_no_docstrings.py

@@ -0,0 +1,12 @@
+# This is a sample module used for testing doctest.
+#
+# This module is for testing how doctest handles a module with no
+# docstrings.
+
+
+class Foo(object):
+
+    # A class with no docstring.
+
+    def __init__(self):
+        pass