Improve enum symbol coverter

[pepone]

Unrelated to this PR, but could we do something like:

var func = builtin.Kind switch {
    BuiltinKind.Int8 => ...
    BuiltinKind.UInt8 => ...
};
return CreateBasicEnum(raw, module, builtin, func);

Instead of repeating the call to CreateBasicEnum in ever case? Because the only thing that actually changes between each case is the lambda we pass, everything else is the same right?

Originally posted by @InsertCreativityHere in #4568 (comment)

[pepone]

I think the current approach works better because the return type is BasicEnum<T> and T is deduced from the function arguments.

If we want to have var func we cannot deduce T in the call to CreateBasicEnum.

[InsertCreativityHere]

Ah okay. I didn't think about the fact each of the lambdas actually has a different type.
Indeed, guess it's best to leave how it is.