Use actual names for Generics instead of T

[jwoertink]

Fixes #836

There's a ton of places where T gets used, so I'll have to take some time to think out if all of them are necessary to change, or if just the ones where named collisions can happen....

[matthewmcgarvey]

I'm not so sure about AvramModel because it hides that it's a generic.

Is it possible to use _T or _Avram_T or something like that?

[jwoertink]

Yeah, I debated on this too. I originally went with ModelT 😂 but it felt so hokey... Maybe _T would be better? I think the discord chat at the time had suggested LuckyT, but that also didn't feel right. Avram_T is a decent option too 🤔

[robacarp]

I have no problem with this. I don't think it's opaque to call it AvramModel, thats what it would look like if it were a type alias, and that's essentially what this is.