ocaml: add page (#3514)

pages/common/ocaml.md

@@ -0,0 +1,12 @@
+# ocaml
+
+> The OCaml repl (read-evaluate-print-loop).
+> Interprets Ocaml commands.
+
+- Read OCaml commands from the user and execute them:
+
+`ocaml`
+
+- Read OCaml commands from a file and execute them:
+
+`ocaml {{path/to/file.ml}}`