Backport #11978: Update SPDX license list to version 3.28

[mergify]

This PR also adds adds a file format changelog for 3.16, which we missed.

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• 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!) N/A

QA Notes

cabal init -n test
cd test/
# Modify the `license:` field to `Advanced-Cryptics-Dictionary`
cabal check  # it should *not* complain about the license

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This is an automatic backport of pull request #11978 done by [Mergify](https://mergify.com).

[mergify]

Queued — the merge queue status continues in this comment ↓.

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-06-20 13:43 UTC · Rule: default
• ✅ Checks passed · on draft merge queue: queuing 3.18 (3782c52) and [#11989 + #11990] together #11991
• ✅ Merged — 2026-06-20 15:44 UTC · at e7e93b4186a84a41f8b63e4e06913662d63dbba3 · merge

This pull request spent 2 hours 28 seconds in the queue, including 1 hour 49 minutes 32 seconds running CI.

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  • Backport #11978: Update SPDX license list to version 3.28 #11989
  • Backport #11970: Run ghc-supported-extensions on CI #11990
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  • Backport #11978: Update SPDX license list to version 3.28 #11989
  • Backport #11970: Run ghc-supported-extensions on CI #11990
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