Fix comment removed when function signature has type keyword (rescript-lang#6997)

* Fix comment removed when function signature has type keyword

* Update CHANGELOG

Author: shulhi

CHANGELOG.md

@@ -16,6 +16,7 @@
 - Fix incorrect format of function under unary operator. https://github.com/rescript-lang/rescript-compiler/pull/6953
 - Fix incorrect incorrect printing of module binding with signature. https://github.com/rescript-lang/rescript-compiler/pull/6963
 - Disallow spreading anything but regular variants inside of other variants. https://github.com/rescript-lang/rescript-compiler/pull/6980
+- Fix comment removed when function signature has `type` keyword. https://github.com/rescript-lang/rescript-compiler/pull/6997
 
 # 11.1.3
 
@@ -2508,4 +2509,4 @@ Features:
 
 # 1.0.0
 
-Initial release
+Initial release

jscomp/syntax/src/res_comments_table.ml

@@ -1404,6 +1404,8 @@ and walkExpression expr t comments =
         attach t.leading expr.pexp_loc leading;
         walkExpression expr t inside;
         attach t.trailing expr.pexp_loc trailing
+    | Pexp_construct ({txt = Longident.Lident "Function$"}, Some returnExpr) ->
+      walkExpression returnExpr t comments
     | _ ->
       if isBlockExpr returnExpr then walkExpression returnExpr t comments
       else