Fix eio_windows types

lib_eio_windows/fs.ml

@@ -172,9 +172,9 @@ end = struct
       with_parent_dir new_dir new_path @@ fun new_dir new_path ->
       Err.run (Low_level.rename ?old_dir old_path ?new_dir) new_path
 
-  let symlink t old_path new_path =
-    with_parent_dir t new_path @@ fun dirfd path ->
-    Err.run (Low_level.symlink old_path dirfd) path
+  let symlink t path ~link_to =
+    with_parent_dir t path @@ fun dirfd path ->
+    Err.run (Low_level.symlink link_to dirfd) path
 
   let close t = t.closed <- true
 

lib_eio_windows/low_level.mli

@@ -47,7 +47,9 @@ val read_link : ?dirfd:fd -> string -> string
 val mkdir : ?dirfd:fd -> ?nofollow:bool -> mode:int -> string -> unit
 val unlink : ?dirfd:fd -> dir:bool -> string -> unit
 val rename : ?old_dir:fd -> string -> ?new_dir:fd -> string -> unit
+
 val symlink : string -> fd option -> string -> unit
+(** [symlink link_to dir path] creates a new symbolic link [dir / path] pointing to [link_to] *)
 
 val readdir : string -> string array