Fix stack ghci ctrl c 3821

[mgsloan]

Note: Documentation fixes for https://docs.haskellstack.org/en/stable/ should target the "stable" branch, not master.

Please include the following checklist in your PR:

• Any changes that could be relevant to users have been recorded in the ChangeLog.md
• The documentation has been updated, if necessary.

Please also shortly describe how you tested your change. Bonus points for added tests!

[dbaynard]

I've rebased this onto current master with dbaynard/stack#fix-stack-ghci-ctrl-c-3821 where it both passes the test suite and fixes the issue. If you want @mgsloan I can PR master directly, replacing this PR?

(Edit: there are some conflicts with very recent commits)

[snoyberg]

Thanks @mgsloan and @dbaynard, merged!

[snoyberg]

@mgsloan I merged in the branch for @dbaynard, but it appears that it didn't completely overlap with your changes here. Can you review and see if this PR can be closed?

[dbaynard]

Yes, please do — it seems fairly straightforward but I'm not familiar with the codebase.

The (non-changelog) conflicting changes were introduced in the 2 commits immediately preceding the base for my rebase.