My aggregated monorepo of OCaml code, automaintained

Restore mdx and directory-targets in dune-project

Monopam sync removes these but mdx is a test dependency and
directory-targets is needed by some packages.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

+3
+3
dune-project
··· 1 1 (lang dune 3.20) 2 2 (name root) 3 3 4 + (using directory-targets 0.1) 5 + 4 6 (generate_opam_files true) 5 7 6 8 (package ··· 37 39 js_of_ocaml-toplevel 38 40 logs 39 41 lwt 42 + (mdx :with-test) 40 43 menhir 41 44 merlin-lib 42 45 ocaml