feature reuqest: extra option to extend, rather than replace, ignoreSigs

[matthewhughes934]

I have a use-case where I would like to add another signature to be ignored by wrapcheck[1], currently this means adding it to ignoreSigs which will stomp any of the defaults, so to keep current behaviour I need to:

• Copy the current defaults to my config under ignoreSigs
• Add another entry for my new signature

I find the current defaults very helpful, so this means I now need to manually keep my list in sync (e.g. if any new values are added as default I will need to also add them to my config).

Request: I was wondering if you would be open to accepting a change that adds a new config option like extraIgnoreSigs to address this, like:

extraIgnoreSigs:
    # ignore all the everything under `ignoreSigs` (or the defaults if that doesn't exist) and additionally:
    - SomeSpecialFunc(
    - SomeOtherFunc(

Currently the same behaviour would require a config like:

ignoreSigs:
# default values
- .Errorf(
- errors.New(
- errors.Unwrap(
- errors.Join(
- .Wrap(
- .Wrapf(
- .WithMessage(
- .WithMessagef(
- .WithStack(
# my extra bits
- SomeSpecialFunc(
- SomeOtherFunc(

I'd be happy to try and get this change up if there's interest

[1] My case was for ignoring google.golang.org/grpc/status.Error, note that package also has google.golang.org/grpc/status.Errorf which is ignored by the .Errorf( sig in the default list, so I was also wondering if .Error( functions might be considered for inclusion in the default list?