message: Comment clarifications suggested by Hudson.
diff: @@ -25,7 +25,7 @@ pub fn schedule(
  None => return Ok(()),
  };
  // Don't bother queueing a null upcall, as they don't do anything when
  - // invoked anyway.
  + // invoked anyway, and the core kernel does not queue them either.
  if upcall.is_null() {
  return Ok(());
  }
  @@ -181,7 +181,7 @@ mod tests {
  crate::kernel_data::with_kernel_data(|kernel_data| {
  let kernel_data = kernel_data.unwrap();
  - // Very the upcall was queued.
  + // Verify the upcall was queued.
  assert_eq!(kernel_data.upcall_queue.len(), 1);
  let upcall_queue_entry = kernel_data.upcall_queue.front().expect("Upcall not queued");
  assert_eq!(upcall_queue_entry.args, (3, 4, 5));
  