Refactor validation errors

[jchadwick-buf]

This contains two main changes:

• Removes alias to pb type from protovalidate-go error interface (closes Un-typedef errors.ValidationError to buf.validate.Violations #52)
• Adds FieldValue and RuleValue to new errors.Violation type, alongside required plumbing

A lot of different approaches were considered, but so far this seems to be the cleanest way to get the desired result. It also has the benefit of removing most of the unnecessary allocations that were added in the error case during the proto2 migration.

I think there is no particularly good reason to keep the Violation message as part of the protovalidate protobuf API, so I think it should be moved to the validation test harness. After further discussion, I think we're not in a position to remove Violation or Violations from the API right now, due to usages outside of protovalidate (e.g. as error details, in connectrpc/validate-go.). We'll need to weigh in on this before 1.0.

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / validate-protos (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Oct 15, 2024, 9:35 PM