Improve ocaml language support

See README.org.

Signed-off-by: Edwin Török <edwin@etorok.net>

modules/lang/ocaml/doctor.el

@@ -0,0 +1,18 @@
+;; -*- lexical-binding: t; no-byte-compile: t; -*-
+;;; lang/ocaml/doctor.el
+
+(unless (executable-find "ocamlmerlin")
+  (warn! "Couldn't find ocamlmerlin. Lookup, completion and syntax checking won't work."))
+
+;; Tuareg can still indent
+(unless (executable-find "ocp-indent")
+  (warn! "Couldn't find ocp-indent. Auto-indentation will be less precise."))
+
+(when (featurep! :feature eval)
+  (unless (executable-find "utop")
+    (warn! "Couldn't find utop. REPL won't be available")))
+
+(unless (executable-find "dune")
+  (warn! "Couldn't find dune. Won't be able to highlight dune files"))
+
+;; ocamlformat is optional, don't warn about it