Fix link

Author: StanFromIreland

documentation/translations/translating.rst

@@ -136,3 +136,5 @@ How should I translate code examples?
 Translate values in code examples (i.e. string literals) and comments.
 Don't translate keywords or names,
 including variable, function, class, argument, and attribute names.
+
+.. _translation_ml: https://mail.python.org/mailman3/lists/translation.python.org/