fix(xan): fix compat with new base+ghc

A couple of changes necessary to get things working with both ghc 8.8.3
and the new base:

- Explicitly import fail from Control.Monad.Fail in the prelude, since
  it's there instead of the base prelude now
- GHC no longer allows type family equality constraints in quantified
  constraints - which is a bummer - but is avoidable in the one case
  where it was happening
- Explicitly import a constructor from Data.List.NonEmpty

Change-Id: Ia06fc724ddc2d6a3f9024c047ed55eea40bcf408
Reviewed-on: https://cl.tvl.fyi/c/depot/+/744
Tested-by: BuildkiteCI
Reviewed-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>

users/glittershark/xanthous/src/Xanthous/Game/Lenses.hs

@@ -111,7 +111,7 @@ characterVisibleEntities game =
 entitiesCollision
   :: ( Functor f
     , forall xx. MonoFoldable (f xx)
-    , forall xx. Element (f xx) ~ xx
+    , Element (f SomeEntity) ~ SomeEntity
     , Element (f (Maybe Collision)) ~ Maybe Collision
     , Show (f (Maybe Collision))
     , Show (f SomeEntity)