Vulkan: Update documentation for enabling debug markers After changes to the GN arg "angle_enable_trace" were done, other GN args are now needed. Bug: b/170249632 Change-Id: Ib5e703434cb580aa838ef8632b271f5f20554f42 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2684933 Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Tim Van Patten <timvp@google.com> Commit-Queue: Ian Elliott <ianelliott@google.com>