message: tracing: document that `event_enabled!` does not call `Collect::event_enabled`
  Although it shares the name, `event_enabled!` *does not* call
  `Collect::event_enabled`. `Collect::event_enabled` is only called once
  the event fields are available.
diff: @@ -806,6 +806,9 @@ macro_rules! event {
  /// This is similar to [`enabled!`], but queries the current collector specifically for
  /// an event, whereas [`enabled!`] queries for an event _or_ span.
  ///
  +/// Although it shares the name, this *does not* call [`Collect::event_enabled`].
  +/// `Collect::event_enabled` is only called once the event fields are available.
  +///
  /// See the documentation for [`enabled!]` for more details on using this macro.
  /// See also [`span_enabled!`].
  ///
  @@ -826,6 +829,7 @@ macro_rules! event {
  /// }
  /// ```
  ///
  +/// [`Collect::event_enabled`]: crate::Collect::event_enabled
  /// [`enabled!`]: crate::enabled
  /// [`span_enabled!`]: crate::span_enabled
  #[macro_export]
  