Changes

Fix docs: runtime warnings are not enabled by default

The docs on this are out of date: they say runtime warnings are enabled by
default, but the source code has a commit 6c90da4 pointing to
https://github.com/ocaml/ocaml/pull/210 that disables them by default.

It seems like enabling runtime warnings by default never made its way into a
release and the docs could just be updated to say that runtime warnings are
disabled by default.

Signed-off-by: Edwin Török <edvin.torok@citrix.com>
 (commit: f66e395)