Updated June 11th, 2019.
There are certain conventions that all Mac apps are supposed to adhere to. One is “put the cursor in the Help menu’s Search field when the user types Command-Shift-?“. Presto– instant help, in any app. Well, in any app that follows the rules, which is most of them.
Try it– it will probably work. And once you get there, type something and see if it’s in the app’s menus.