Duh!!  After much playing around, including downloading the github sublime-syntax and tmPreferences files, I FINALLY found the toggle on the page. Looks like there's a superb manual on iOS - but nothing yet on Mac.  

Screenshot below for the "hard of thinking" like me.... and you get a pop-up list of 80+ syntax highlighters!

Follow up on the previous question.  I've found: https://github.com/sublimehq/Packages/tree/master/SQL but the difficulty is really the user-guide - there isn't one for mac.  (Aside from Emmet https://docs.emmet.io) and one page on how to configure new languages. 

While you don't need to explain how to do "search and replace" - a quick note / demo on how to install syntax highlighting would be helpful.  Thanks!