update max supported ghc to <9.16

[geekosaur]

Template Α: This PR modifies behaviour or interface

Include the following checklist in your PR:

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
  • Is the change significant? If so, remember to add significance: significant in the changelog file.
• The documentation has been updated, if necessary.
• Manual QA notes have been included.
• Tests have been added. (Ask for help if you don’t know how to write them! Ask for an exemption if tests are too complex for too little coverage!)

[ulysses4ever]

Thanks!

[Mikolaj]

Oh, cool, thanks to #10663 this seems to be enough. Let me update the release checklist wiki to reflect this.