Enter key should be the same as "Submit" in the popups

[mdroidian]

Issue raised by @mattakamatsu in Smartblocks: RoamJS/smartblocks#130

I want to be able to enter the dialog (popup) inputs entirely from my keyboard. This would increase the time I'm in flow when making pages. I can navigate and enter all fields, except clicking a checkbox (which isn't a big deal) and "Submit" (which requires me from leaving the keyboard). I'd like to be able to hit Enter, and have that be the same as "Submit" for these popup dialogs.

https://www.loom.com/share/cdf1d58d4f4e48aaa532f0330b06e2a7?sid=f448f640-1ce2-4c92-94cb-94eee78d4dee

[mattakamatsu]

Note that tab (to the submit button) + enter solves like 90% of my use cases, so this addition is not pressing