ox-latex.el: Use [Objective]Caml dialect

* ox-latex.el (org-latex-listings-langs): Change the binding for
  `ocaml' to "[Objective]Caml"

The "[Objective]Caml" dialect syntax highlighting is different from the
"Caml" one (reflecting the added features of OCaml compared to
Caml-light).

TINYCHANGE

lisp/ox-latex.el

@@ -956,7 +956,7 @@ URL `https://orgmode.org/worg/org-tutorials/org-latex-preview.html'."
     (tex "TeX") (latex "[LaTeX]TeX")
     (shell-script "bash")
     (gnuplot "Gnuplot")
-    (ocaml "Caml") (caml "Caml")
+    (ocaml "[Objective]Caml") (caml "Caml")
     (sql "SQL") (sqlite "sql")
     (makefile "make")
     (R "r"))