Emits the new OverloadFlag::kMustUse flag on the annotated overloads.
Nothing consumes this, yet.
Bug: tint:1844
Change-Id: I4eb0943a23eaf5de98cd63444a686cffe62fb36e
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/120920
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Auto-Submit: Ben Clayton <bclayton@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>