EPA: Match GHC replacing Monoid with NoAnn

Also tidies up the NFData NameAnn instance for NameAnnRArrow

GHC #20372

haddock-api/src/Haddock/Convert.hs

-{-# LANGUAGE CPP           #-}
-{-# LANGUAGE PatternGuards #-}
-{-# LANGUAGE TypeFamilies  #-}
-{-# LANGUAGE BangPatterns  #-}
+{-# LANGUAGE CPP              #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE PatternGuards    #-}
+{-# LANGUAGE TypeFamilies     #-}
+{-# LANGUAGE BangPatterns     #-}
 
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