* feat(haskell): add haskell module and implement ghc version detection
* feat(haskell): implement stack resolver version detection
* fix(haskell): handle more complex resolvers
* fix(haskell): rename resolver_version to snapshot
* fix(haskell): change default color to bold purple
* feat(haskell): add tests
* fix(haskell): format
* fix(haskell): replace incorrect `or` with `or_else`
* fix(haskell): use write_all instead of write
* fix(haskell): λ as Haskell icon by default
* fix(haskell): fix tests and add a real stack.yaml testcase
* fix(haskell): make clippy happy