Update Rust grammar from upstream repository

[Wilfred]

PR #194614 aimed to include the commit
dustypomerleau/rust-syntax@328a682 but it looks like it actually took the prior commit.

Update the grammar to correctly reflect the upstream repo.

[alexr00]

@Wilfred thanks for the PR! That the commit and the file contents don't match indicates a bigger problem. I first suspected a problem with the tooling we use to pull in grammar updates (and there is an issue where the commit doesn't match the contents), but the bigger problem is that https://github.com/dustypomerleau/rust-syntax has both a main branch and a master branch, and the main branch is set as the default branch. It looks like main and master have diverged. In VS Code, we can only pull from one branch. We were incorrectly pulling from master since main is the default branch.

I will update VS Code to pull from main, but since main and master have diverged you might want to reconcile them and/or delete master.

[alexr00]

PR with the fix for VS Code is here: #194787

[Wilfred]

@alexr00 Thanks, that's super helpful. To be clear, are you periodically pulling from the upstream repo, or should I be submitting PRs here when I merge PRs on the upstream repo?

[alexr00]

I pull changes from upstream grammar repos about once per month via a script, usually at the very beginning of our development iteration. If there's a change that you think should be pulled immediately you can @ mention me and I can pick the changes up more immediately.