Capability Versions Save

Fix compatibility with GHC 9.0. See #96

Remove Capability.Writer.Discouraged. This module incurred a dependency on monad-unlift which is no longer available for GHC 9.0. Given that its use was discouraged, it was deemed best to remove it. See #96

Added censor function to Capability.Writer. See #94

Fix infinite loop in writer. See #85

Introduce Capability.Reflection to define ad-hoc interpreters. See #86

Fix compatibility with GHC 8.10. See #87