Behaviour addition: Allow par-spacing on HsApp

source/library/Language/Haskell/Brittany/Internal/ToBriDoc/Expr.hs

@@ -165,6 +165,23 @@ layoutExpr lexpr@(L _ expr) = do
           $ colsOrSequence
           $ appSep (docForceSingleline headDoc)
           : spacifyDocs (docForceSingleline <$> paramDocs)
+        -- foo x do
+        --   a
+        --   b
+        -- foo x \meow -> do
+        --   a
+        --   b
+        addAlternativeCond (not hasComments) $ docSetParSpacing $ docSeq
+          [ appSep (docForceSingleline headDoc)
+          , case splitFirstLast paramDocs of
+              FirstLastEmpty -> docEmpty
+              FirstLastSingleton e1 -> docForceParSpacing e1
+              FirstLast e1 ems eN ->
+                docSeq
+                  (  spacifyDocs (docForceSingleline <$> (e1:ems))
+                  ++ [docSeparator, docForceParSpacing eN]
+                  )
+          ]
         -- foo x
         --     y
         addAlternativeCond allowFreeIndent $ docSeq