message: Change the warning message.
diff: @@ -14,7 +14,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  let this = self.eval_context_mut();
  this.tcx.sess.warn(
  - "The thread support is experimental. \
  + "thread support is experimental. \
  For example, Miri does not detect data races yet.",
  );
  