Remove camlp4 reference from the manual

[bobbypriam]

Solves #449.

Removes camlp4 reference, since its use has been deprecated. The "Correspondence table" is also updated to use the Ppx syntax.

[bobbypriam]

There is still one reference left of camlp4 in The logging facility section. I'm not sure what to do with it, should I just delete it altogether?

[aantron]

Probably the best is to replace it by some kind of summary of, or reference to, the PPX logging support section https://ocsigen.org/lwt/3.0.0/api/Ppx_lwt#2_Logging.

[aantron]

It looks good. The only thing I'd recommend is adding an example of a command line for triggering the PPX, i.e. with ocamlfind ... -package lwt.ppx ... (hope I didn't miss it if it's already there). We had the equivalent for Camlp4.

[aantron]

And don't worry about the 4.06+trunk build failure – that's clearly an upstream problem. I'll move it to allowed_failures later in master.

[aantron]

(And if you'd like to see more details on that upstream issue, ocaml-ppx/ocaml-migrate-parsetree#19 (comment)).

[bobbypriam]

I've updated the PR with the example to use lwt.ppx on ocamlfind and toplevel, and a reference to Ppx_lwt Logging section.

Sorry for the late commits, timezone issues 🙂

[aantron]

Looks good. Thanks!

[aantron]

Checked the generated version online (it's hard to do so ahead of time). It looks good as well.

[bobbypriam]

That's good to hear, and thanks for letting me take this!