Fix dead ScanCode Toolkit documentation link

Author: Vijya2024

docs/source/contributing.rst

@@ -73,7 +73,8 @@ overlooked. We value any suggestions to improve
 
 .. tip::
     Our documentation is treated like code. Make sure to check our
-    `writing guidelines <https://scancode-toolkit.readthedocs.io/en/latest/contribute/contrib_doc.html>`_
+    `writing guidelines <https://scancode-toolkit.readthedocs.io/en/stable/contribute/
+>`_
     to help guide new users.
 
 Other Ways