Use SetterInput for more setters

[griff]

This changes more of the setters both manually implemented and generated to accept a SetterInput.

This makes it useful to implement SetterInput on your own types to support using them with setters.

This is especially useful when you have plain rust structs the represent the capnp-struct and you just want convert one to the other and is my main use case.

I don't know if this is a breaking change like how originally implementing SetterInput was.