Mark haml_lint and gitlab-styles as tooling gems

What does this MR do and why?

Mark haml_lint and gitlab-styles as tooling gems.

Marking them so we can remove them from https://gitlab.com/gitlab-org/frontend/renovate-gitlab-bot/-/blob/74fb253b3c1aaee73607e6c2046c03a545e05095/renovate/gitlab/ruby.config.js#L26

And they can upgrade independently.

This is a proposal from !147577 (comment 1827499366)

Renovate merge request: gitlab-org/frontend/renovate-gitlab-bot!806 (merged)

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