Add stackoverflow link to related.rst

Author: matusvalo

doc/data/messages/d/duplicate-key/related.rst

@@ -1,2 +1,2 @@
-`Python Dictionaries <https://docs.python.org/3/tutorial/datastructures.html#dictionaries>`_
-`Mapping Types — dict <https://docs.python.org/3/library/stdtypes.html#typesmapping>`_
+* `Python Dictionaries <https://docs.python.org/3/tutorial/datastructures.html#dictionaries>`_
+* `Mapping Types — dict <https://docs.python.org/3/library/stdtypes.html#typesmapping>`_