Allow generic arguments in enum variants

[AlephAlpha]

Allow generic arguments in enum variants, for example:

#[proxy_enum::proxy(Animal)]mod proxy {usesuper::{Cat,Foo,Lion,Mouse};enumAnimal{Cat(Cat<Foo>),Lion(Lion),Mouse(Mouse),}implAnimal{#[implement]fnfeed(&self){}}}

This would expand to:

mod proxy {usesuper::{Cat,Foo,Lion,Mouse};enumAnimal{Cat(Cat<Foo>),Lion(Lion),Mouse(Mouse),}implAnimal{fnfeed(&self){matchself{Self::Cat(__self) => <Cat<Foo>>::feed(__self),Self::Lion(__self) => <Lion>::feed(__self),Self::Mouse(__self) => <Mouse>::feed(__self),}}}implFrom<Cat<Foo>>forAnimal{fnfrom(from:Cat<Foo>) -> Self{Animal::Cat(from)}}implFrom<Lion>forAnimal{fnfrom(from:Lion) -> Self{Animal::Lion(from)}}implFrom<Mouse>forAnimal{fnfrom(from:Mouse) -> Self{Animal::Mouse(from)}}}

The < and > around the type are only added for inherent implementations, not trait implementations.

[AlephAlpha]

Sorry for my username. It's just a coincidence.