Consider adding "debug" information to root errors

[morningvera]

Occasionally, it could be a good idea to create a new error with a type and some debug info (e.g. eris.New(type string, info string), eris.New("error not found", "sql no rows")). This will make comparing errors to error not found easy while also letting users add debug context to new errors (which could be shown or not based on a format option). This could also make it easier to send debug info to logs while hiding debug info from clients.

[morningvera]

I don't think there's a major need for this. Closing it for now.