fix: use errors.New for const errors

[cristaloleg]

Overview

Small cleanup PR. Use errors.New when parameter is const (instead of fmt.Errorf).

[Wondertan]

Is there a fundamental difference between those? I always assumed the resulting errors are sort of identical

[cristaloleg]

Nah, underneath, it will be the same error—the only thing why errors.New is better in this context is that nobody in the future will ask: are we missing params here?

(Hmm, I recall one more pro: when we migrated to another error library, we had a smaller diff due to the absence of such patterns).

[renaynay]

Fine with this, thanks :)