message: Use idiomatic is_some()
diff: @@ -125,12 +125,13 @@ impl Manifest {
  workers_dot_dev to toggle between publishing to your workers.dev subdomain and your own domain.";
  // Check for the presence of the 'private' field in top-level config; if present, warn.
  - if let Some(_) = self.private {
  + if self.private.is_some() {
  message::warn(deprecate_private_warning);
  }
  +
  // Also check for presence of 'private' field in a provided environment; if present, warn
  if let Some(e) = environment {
  - if let Some(_) = e.private {
  + if e.private.is_some() {
  message::warn(deprecate_private_warning);
  }
  }
  