RTL hook documentation

Hi Rich,

The documentation is "live" at https://www.liferay.com/documentation/liferay-portal/6.2/development/-/ai/displaying-rtl-content-with-rtl-hook-liferay-portal-6-2-dev-guide-11-en for the hook's release today.

https://issues.liferay.com/browse/LRDOCS-986

It's ready for upstream.

Thanks,
Jim