message: comment rustfmt when preparing beta
diff: @@ -94,6 +94,7 @@ branch of rust-lang/rust which:
  - Change `rustc` to "X.Y.Z" where that's the version of rustc you just build
  - Change `cargo` to "A.B.C" where it's Cargo's version. That's typically
  "0.(Y+1).0" wrt the rustc version.
  + - Comment `rustfmt: nightly-YYYY-MM-DD`
  - Uncomment `dev: 1`
  - Update src/ci/run.sh to pass "--release-channel=beta".
  