Docs: add GC user docs (#58733)
Co-authored-by: Andy Dienes <51664769+adienes@users.noreply.github.com>
Co-authored-by: Gabriel Baraldi <28694980+gbaraldi@users.noreply.github.com>
Co-authored-by: Diogo Netto <61364108+d-netto@users.noreply.github.com>
