Removing more warning flags for GHC backwards compatibility.

Author: recursion-ninja

mono-traversable-keys.cabal

@@ -72,16 +72,12 @@ library
       -fwarn-incomplete-record-updates
       -fwarn-incomplete-uni-patterns
       -fwarn-missing-fields
-      -fwarn-missing-monadfail-instances
       -fwarn-missing-signatures
       -fwarn-overflowed-literals
       -fwarn-overlapping-patterns
-      -fwarn-redundant-constraints
-      -fwarn-semigroup
       -fwarn-tabs
       -fwarn-unused-binds
       -fwarn-unused-do-bind
-      -fwarn-unused-foralls
       -fwarn-unused-imports
       -fwarn-unused-matches
       -fwarn-wrong-do-bind