How to get Atom to reload automatically when I update language grammar rules?

I’m writing some custom grammar rules and find it frustrating that I have to perform finger gymnastics every time I need to hit Ctrl-Shift-F5 to reload the editor.

Is there a way to have the rules update automatically so that any changes to the grammar rules will automatically update when switch to the tabs I’m previewing?

I found that there is a --dev mode. I’ve been unable to make this work for grammar rules. If this is indeed supported, would someone please provide a clear step-by-step process on how to get this working?

Thank you.