Specify not-home in Data.MonoidMap.Internal.

For the purposes of public API documentation, we want to arrange that
haddock will not treat `Data.MonoidMap.Internal` as a home module for
functions and types re-exported from `Data.MonoidMap`.

Author: jonathanknowles

components/monoidmap-internal/Data/MonoidMap/Internal.hs

@@ -1,5 +1,6 @@
 {-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
 {-# OPTIONS_GHC -fno-warn-unused-imports #-}
+{-# OPTIONS_HADDOCK not-home #-}
 {- HLINT ignore "Avoid lambda" -}
 {- HLINT ignore "Avoid lambda using `infix`" -}
 {- HLINT ignore "Redundant bracket" -}