Another orphan instance issue

[parsonsmatt]

We took quite a while debugging a build error where the Test.QuickCheck.Instances instance of Arbitrary Text was causing problems, and we could not figure out where it was coming from. After quite a lot of investigating, it was revealed to come from this package, where the module is imported here.

Between #91 and this issue, we've lost a considerable amount of time to orphan instances due to this package.

Orphan instances like these can be acceptable in test suites and executables, but they really can cause a lot of problems in libraries.

Would you be willing to accept a PR that tidies up the orphan instances and prevents them from leaking throughout the codebase?

[frasertweedale]

Thanks for the report.

I expect to have capacity in April to deal with these issues.

[parsonsmatt]

Thank you!