[copilot] yaml syntax errors with location #100
Description
- Use the Go package https://pkg.go.dev/github.com/goccy/go-yaml to parse the front matter yaml
- Use https://pkg.go.dev/github.com/goccy/go-yaml builtin error support to generate errors
- When error location (line, column) is unknown, do not provide 1,1. It is confusing.