* Add `Span#Error` method to simplify setting an error status and message.
* `Span#Error` should no-op on nil errors
* Record errors as a span event rather than status/attributes.
The implementation in the SDK package now relies on existing API methods.
* Add WithErrorStatus() ErrorOption to allow setting span status on error.
* Apply suggestions from code review
Co-Authored-By: Krzesimir Nowak <qdlacz@gmail.com>
* Address code review feedback
* Clean up RecordError tests
* Ensure complete and unique error type is recorded for defined types
* Avoid duplicating logic under test in tests
* Move TestError to internal/testing package, improve RecordError test scenarios
Co-authored-by: Krzesimir Nowak <qdlacz@gmail.com>
