Add JSDoc comment for "context" autocomplete

[stepjue]

May or may not be helpful depending on other people's environments, but I found myself adding this JSDoc comment in each new project so that I get autocomplete of the "context" parameter in VSCode

[mattdesl]

Cool tip! I think it's a bit too VSCode specific to add to the core but I'll consider it. It would be great if I could somehow document all of this in the core lib itself (maybe with TS typings) so that it's transparent to end-user.