docs: move contributing+debugging to section contributing

docs/mkdocs.yml

@@ -62,8 +62,9 @@ nav:
       - Authoring:
           - Modules: clanmodules/index.md
           - Disk Templates: manual/disk-templates.md
-      - Contribute: manual/contribute.md
-      - Debugging: manual/debugging.md
+      - Contributing:
+          - Contribute: contributing/contribute.md
+          - Debugging: contributing/debugging.md
       - Repo Layout: manual/repo-layout.md
       - Migrate existing Flakes: manual/migration-guide.md
   # - Concepts:

docs/site/index.md

@@ -63,7 +63,7 @@ hide:
 
     Use clan with [https://flake.parts/]()
 
--   [Contribute](./manual/contribute.md)
+-   [Contribute](./contributing/contribute.md)
 
     ---