"/" still needs to be escaped in custom operators

Looks like I'm hitting the same issue, as discussed in #609. Cross-posting my comments from that closed issue:

Looks like there are stil issues with operators with / inside. The following code snippet is formatted from OCaml and results in syntax error (try link), until I escape (use <\/> operator instead):

let routes =
  Routes.(
    Infix.(
      Handlers.(
        with_method([
          (`GET, return_bigstring <$ empty),
          (`GET, greeter <$> s("greet") *> int </> str </> str),
          (`GET, sum <$> s("sum") *> int (</>) int),
        ])
      )
    )
  );

What's even worse, refmt removes those escapings, making the code unparseable again.

dune version: 1.10.0
esy version: 0.5.6
refmt version: Reason 3.3.7 @ 43efc14

Start with the supplied Reason snippet and the reported refmt version, reproducing the syntax error and the formatter's removal of the escaping. Trace how custom operators containing / are parsed and formatted; done means the example parses successfully and refmt preserves valid escaping.