Fix #9318 Avoid Haddock warning with haddock --for-hackage

[mpilgrem]

The logic of this change is simple: if the existing condition for the use of Haddock's --hyperlinked-source flag is met, don't also include the existing logic for the use of Haddock's --source-* options.

Include the following checklist in your PR:

• Patches conform to the coding conventions. I have followed the style of the surrounding code.
• Any changes that could be relevant to users have been recorded in the changelog. I don't think this change is worthy of an entry in the Change Log.
• The documentation has been updated, if necessary. The underlying feature is undocumented, so there is no documentation to update.
• Manual QA notes have been included. I've included code comments. I don't think QA notes are required.

Bonus points for added automated tests!

[geekosaur]

Fourmolu doesn't think you folllowed the style closely enough, apparently.

[mpilgrem]

@geekosaur, sorry on formatting; trying again.

[mpilgrem]

@geekosaur, I think the CI is failing for reasons unconnected with this pull request (based, in part, on this comment: #9320 (comment) which refers to the same problem in terms that suggest it is a familiar problem).

[Mikolaj]

Oh, yes, the "directory-1.3.8.1 directory-1.3.8.1" CI problem strikes again. Let me restart the jobs and if everything else fails, I will wipe out CI cache.

[Mikolaj]

It failed in the same way. Let me clear the GHA cache.

[Mikolaj]

Clearing GHA cache of master branch with https://github.com/haskell/cabal/actions/caches fixed the issue this time.

@mpilgrem: apologies for the inconvenience and thank you for the PR. ;)