Two fixes to DevSetup.md Change master->main and eliminate a redundant/premature Linux instruction. Bug: angleproject:0 Change-Id: Ic7171f860de8acc22050a4d4858cfd318f36b9e3 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3035863 Commit-Queue: Ian Elliott <ianelliott@google.com> Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>