docs: fix links of PY rules in packaging_simple.md (#362)

* docs: fix links of PY rules in packaging_simple.md

* style: pre-commit fixes

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: tkoyama010

docs/pages/guides/packaging_simple.md

@@ -98,8 +98,8 @@ for very special cases), you will likely need extra configuration here.
 
 You should have a `README` {% rr PY002 %} and a `LICENSE` {% rr PY003 %} file.
 You should have a `docs/` folder {%
-rr PY003 %}. You should have a `/tests` folder (recommended) and/or a `src/<package>/tests`
-folder.
+rr PY004 %}. You should have a `/tests` folder {%
+rr PY005 %} (recommended) and/or a `src/<package>/tests` folder.
 
 ## Versioning