Add sample for onCallGenkit

[jhuleatt]

There are a lot of snippet tags in here because I want to make sure we can get close to matching all the snippets currently hardcoded into https://github.com/firebase/genkit/blob/main/docs/firebase.md

[egilmorez]

That IS a lot of tags! But if you have mapped them to the existing snippets, that makes a world of sense.

Though we are inconsistent about it in other samples, it would be great to have basic punctuation in any comments that are displayed in the docs -- mainly periods in this file.

Are you game to do an add-periods scrub, and then if I can find anything else I'll comment specifically? Thanks Jeff!

[egilmorez]

LGTM! Eager to get the snippets generated. :)

[jhuleatt]

That IS a lot of tags! But if you have mapped them to the existing snippets, that makes a world of sense.

Though we are inconsistent about it in other samples, it would be great to have basic punctuation in any comments that are displayed in the docs -- mainly periods in this file.

Are you game to do an add-periods scrub, and then if I can find anything else I'll comment specifically? Thanks Jeff!

I've added punctuation and clarified some comments - going to merge now so you can generate snippets!