Limit the number of valid hole fits

Originally haskell/ghcide#888

Author: expipiplus1

ghcide/src/Development/IDE/GHC/Compat.hs

@@ -184,6 +184,7 @@ import           Data.List              (foldl')
 import           Data.List              (foldl', isSuffixOf)
 #endif
 
+import           Control.Applicative    ((<|>))
 import qualified Data.Map               as M
 import           DynamicLoading
 import           Plugins                (Plugin (parsedResultAction),
@@ -303,7 +304,7 @@ setUpTypedHoles df
   $ df
   { refLevelHoleFits = Just 1   -- becomes slow at higher levels
   , maxRefHoleFits   = Just 10  -- quantity does not impact speed
-  , maxValidHoleFits = Nothing  -- quantity does not impact speed
+  , maxValidHoleFits = maxValidHoleFits df <|> Just 10  -- quantity does not impact speed
   }