Refactor comment parsing to use odoc-parser and cmarkit

Omd 2.X doesn't support printing markdown, so OCaml LSP is blocked to Omd 1.X. This creates conflicts with codebases that have migrated to Omd 2.X (e.g. in ocamlorg).

To avoid conflicts for users of Omd 2.X, we migrate to cmarkit, which has a smaller dependency profile and supports printing to markdown.

Co-authored-by: Rafał Gwoździński <rafal.gwozdzinski@gmail.com>

dune-project

@@ -56,11 +56,11 @@ possible and does not make any assumptions about IO.
   ordering
   dune-build-info
   spawn
+  (cmarkit (>= 0.2.0))
+  (odoc-parser (>= 2.0.0))
   (ppx_expect (and (>= v0.15.0) :with-test))
   (ocamlformat (and :with-test (= 0.24.1)))
   (ocamlc-loc (and (>= 3.5.0) (< 3.7.0)))
-  (omd (and (>= 1.3.2) (< 2.0.0~alpha1)))
-  (octavius (>= 1.2.2))
   (uutf (>= 1.0.2))
   (pp (>= 1.1.2))
   (csexp (>= 1.5))

flake.nix

@@ -76,8 +76,8 @@
               duneVersion = "3";
               buildInputs = with pkgs.ocamlPackages; [
                 ocamlc-loc
-                omd
-                octavius
+                odoc-parser
+                cmarkit
                 dune-build-info
                 re
                 dune-rpc

ocaml-lsp-server.opam

@@ -32,11 +32,11 @@ depends: [
   "ordering"
   "dune-build-info"
   "spawn"
+  "cmarkit" {>= "0.2.0"}
+  "odoc-parser" {>= "2.0.0"}
   "ppx_expect" {>= "v0.15.0" & with-test}
   "ocamlformat" {with-test & = "0.24.1"}
   "ocamlc-loc" {>= "3.5.0" & < "3.7.0"}
-  "omd" {>= "1.3.2" & < "2.0.0~alpha1"}
-  "octavius" {>= "1.2.2"}
   "uutf" {>= "1.0.2"}
   "pp" {>= "1.1.2"}
   "csexp" {>= "1.5"}