Document functional options (#1899)
Document functional options (#1899)

* Document functional options

* Update CONTRIBUTING.md

Co-authored-by: Tyler Yahn <b79042b10fd9cd75597e3dac7c4e4fe9e14fe996@users.noreply.github.com>

* Update CONTRIBUTING.md

Co-authored-by: Tyler Yahn <b79042b10fd9cd75597e3dac7c4e4fe9e14fe996@users.noreply.github.com>

Co-authored-by: Tyler Yahn <b79042b10fd9cd75597e3dac7c4e4fe9e14fe996@users.noreply.github.com>
Co-authored-by: Anthony Mirabella <bb65d5af60f06ca654295bbce73e2d43310f732e@aneurysm9.com>
open-telemetry/opentelemetry-go,open-telemetry/opentelemetry-go