Fix space between paren and multi-line lambda

data/15-regressions.blt

@@ -956,3 +956,13 @@ func = other $ meep
   [q|hello
      world|]
   (some other very long linnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnne)
+
+#test multiline-lambda-whitespace
+func =
+  Text.intercalate
+    "\n"
+    (   (\(abc, def) ->
+           abc ++ def ++ "lkajsdljkasdlkjasldjkljkasd" ++ asdasdasdasd
+        )
+    <$> mylist
+    )

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

@@ -223,7 +223,10 @@ layoutOpTree allowSinglelinePar = \case
   coreAlternative hasParen locO locC fixity docL sharedOps sharedOpsFlat lastWrap
     = do
       indentPolicy <- askLayoutConf _lconfig_indentPolicy
-      let wrapParenIfSl x inner = if x then wrapParenSl inner else docSetParSpacing inner
+      let zeroOps = null sharedOps
+          wrapParenIfSl x inner = if x
+            then wrapParenSl inner
+            else docSetParSpacing inner
           wrapParenSl inner = docAlt
             [ docSeq
               [ docLit $ Text.pack "("
@@ -241,7 +244,7 @@ layoutOpTree allowSinglelinePar = \case
           wrapParenMl innerHead innerLines = docSetBaseY $ docLines
             (  [ docCols
                    ColOpPrefix
-                   [ appSep $ docLit $ Text.pack "("
+                   [ (if zeroOps then id else appSep) $ docLit $ Text.pack "("
                    , docHandleComms locO $ innerHead
                    ]
                ]