Tighten Vale exceptions for platform servers in file names

[maximiliankolb]

This is great, thanks a lot for taking the time to do this.

I think https://github.com/theforeman/foreman-documentation/blob/master/scripts/check-filename-id-heading-match.sh might also need updating to drop some of the normalizations without dashes. Do you want to look into it in this PR, or shall I try in a follow-up one?

Originally posted by @aneta-petrova in #5038 (review)