Rename dirtraversal rule and change CWE to be more correct
Renames rule-dirtraversal
to rule-httprootdir
to better reflect what is actually being detected. The assigned CWE is also changed to one that is more accurate to the finding. Lastly, test annotations have been added to the related test file.
Part of Enhance Go semgrep rules (gitlab-org/gitlab#409443 - closed)