Use aliases for declaring context and update arguments

[jmattheis]

Goverter could use the addition of generic type aliases (go1.24), to declare arguments as context or update argument. E.g. the following converter

// goverter:converter
type Converter interface {
    // goverter:update target
    ConvertUpdate(source Input, target *Output) error
    // goverter:context dateFormat
    ConvertContext(source map[string]Input, dateFormat string) map[string]Output
}

could be written as

import "github.com/goverter/arg"

// goverter:converter
type Converter interface {
    ConvertUpdate(source Input, target arg.Target[*Output]) error
    ConvertContext(source map[string]Input, dateFormat arg.Context[string]) map[string]Output
}

where github.com/goverter/arg would contain something like:

type Context[T any] = T
type Target[T any] = T

Please 👍 this issue if you like this functionality. If you have a specific use-case in mind, feel free to comment it.