Fix handling of comment before data-decl

`docWrapNodePrior` caused duplication of offset of `data` keyword
and of comments connected to it.

src-literatetests/10-tests.blt

@@ -385,6 +385,11 @@ data Foo = forall a b . (Show a, Eq b) => Bar
   , bars :: b
   }
 
+#test plain comment simple
+-- before
+data MyData = MyData Int
+-- after
+
 #test record comments simple
 data Foo = Bar -- a
   { foo  :: Baz -- b

src/Language/Haskell/Brittany/Internal/Layouters/DataDecl.hs

@@ -46,6 +46,7 @@ layoutDataDecl ltycl name (HsQTvs _ bndrs) defn = case defn of
 #else
 layoutDataDecl ltycl name (HsQTvs _ bndrs _) defn = case defn of
 #endif
+  -- newtype MyType a b = MyType ..
 #if MIN_VERSION_ghc(8,6,0)   /* ghc-8.6 */
   HsDataDefn _ext NewType (L _ []) _ctype Nothing [cons] mDerivs -> case cons of
     (L _ (ConDeclH98 _ext consName (L _ False) _qvars (Just (L _ [])) details _conDoc)) ->
@@ -74,6 +75,9 @@ layoutDataDecl ltycl name (HsQTvs _ bndrs _) defn = case defn of
           ]
     _ -> briDocByExactNoComment ltycl
 
+
+  -- data MyData a b
+  -- (zero constructors)
 #if MIN_VERSION_ghc(8,6,0)   /* ghc-8.6 */
   HsDataDefn _ext DataType (L _ lhsContext) _ctype Nothing [] mDerivs ->
 #else
@@ -90,6 +94,8 @@ layoutDataDecl ltycl name (HsQTvs _ bndrs _) defn = case defn of
         , appSep tyVarLine
         ]
 
+  -- data MyData = MyData ..
+  -- data MyData = MyData { .. }
 #if MIN_VERSION_ghc(8,6,0)   /* ghc-8.6 */
   HsDataDefn _ext DataType (L _ lhsContext) _ctype Nothing [cons] mDerivs ->
 #else

src/Language/Haskell/Brittany/Internal/Layouters/Decl.hs

@@ -748,7 +748,6 @@ layoutTyCl ltycl@(L _loc tycl) = case tycl of
 #else
   DataDecl name tyVars dataDefn _ _ ->
 #endif
-    docWrapNodePrior ltycl $
     layoutDataDecl ltycl name tyVars dataDefn
   _ -> briDocByExactNoComment ltycl