Reference Melange docs

Signed-off-by: Marek Kubica <marek@tarides.com>

doc/reference/files/dune-project/dialect.rst

@@ -77,8 +77,5 @@ In the default configuration Dune comes with two dialects pre-set and enabled:
 * ``reason`` for the Reason syntax and enabled in `.re`/`.rei` files. For
   formatting ``refmt`` is used.
 
-When ``(using melange)`` is enabled in the `dune-project` a third dialect is
-enabled:
-
-* ``rescript`` for the ReScript syntax which is used in `.res` and `.resi`
-  files. The formatter in this case is ``rescript_syntax``.
+A third dialect called ``rescript`` is added when Melange (see :doc:`melange`)
+is enabled in the project.