Fix optional test-suite/benchmark type docs

[cydparser]

Addresses documentation changes requested in PR #8115. I've reverted some additional changes that I made, since the original PR made type optional for all cabal-version's, but PR #8138 limited change to versions >= 3.8.

[ulysses4ever]

@cydparser thank you! Feel free to apply the merge-me label when you're ready (or signal if you don't have the permissions). It will take two more days for Mergify to merge.

[Mikolaj]

@mergify rebase

[mergify[bot]]

rebase

✅ Branch has been successfully rebased

[Mikolaj]

Let me rebase to include a workaround to our CI instability and fix the tests.

[Mikolaj]

@mergify rebase

[mergify[bot]]

rebase

✅ Branch has been successfully rebased

[Mikolaj]

@mergify backport 3.8

[mergify[bot]]

backport 3.8

✅ Backports have been created

• #8397 Fix optional test-suite/benchmark type docs (backport #8344) has been created for branch 3.8