Match error handlers using "errors" package

[bkmeneguello]

Currently the error handler converts the registered errors to a string and the matcher just matches the string representation of the provided error. If the error is wrapped inside another error this check fails.

My suggestion is registering the error handlers either as an error reference or an interface {Error() string} type, and use the methods errors.Is and errors.As to match them.

[survivorbat]

Hey @bkmeneguello, thanks for the suggestion! This sounds like a great improvement. I do think it'd require a change in the interface of the ErrorRegistry, to be able to register an instantiated object in the registry map. So a v3 would likely be necessary. Something like RegisterErrorHandler[E error](error, func (context.Context, error) (int, any) perhaps.

I'll play around with it and see what a v3 could look like :)

[survivorbat]

Could you check out #8? 😎