Add NFData instances

[rm41339]

This PR adds the NFData instances necessary for the HLS plugins to function, as recommended here: haskell/haskell-language-server#4615 (comment)

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
• The documentation has been updated, if necessary.
• [N/A] Manual QA notes have been included.
• [N/A] 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!)

[ffaf1]

Oh I did not see this was not marked as review-needed. Feel free to ignore my comments.

[ulysses4ever]

"cabal.project plugin" looks confusing in the context of the Cabal repository. Please, replace all of its occurrences with "cabal.project HLS plugin" (esp. the changelog).

[ulysses4ever]

@ffaf1 I consider the review-needed label more of our manegerial stuff (to notify Matrix, review during the meetings, and such) rather than an interface for contributors. In practice (I find), when people don't want reviews, they put the PR in the draft state (mostly) because they don't know about the label. So, if the PR isn't in the draft state, it's safe to assume that it can be reviewed, I think.

[fendor]

"cabal.project plugin" looks confusing in the context of the Cabal repository. Please, replace all of its occurrences with "cabal.project HLS plugin" (esp. the changelog).

These instances are also useful for the hls-cabal-plugin, so perhaps a more general HLS is sufficient.

[geekosaur]

Agree with @ffaf1 but otherwise fine.

[fendor]

LGTM! Thank you!

[geekosaur]

Looks like there's a couple of rebase conflicts that need to be fixed.

[ulysses4ever]

@ffaf1 I resolved your older comments: they were straightforward to address and this was done. We can now move forward.

[fendor]

Whitespace change, otherwise, I think you can apply the merge label :)