message: subscriber: fix outdated formatter docs
  This fixes outdated statements in the docs for the `Full` and `Compact`
  logging formats.
  Closes
diff: @@ -301,13 +301,17 @@ pub struct FieldFnVisitor<'a, F> {
  }
  /// Marker for `Format` that indicates that the compact log format should be used.
  ///
  -/// The compact format only includes the fields from the most recently entered span.
  +/// The compact format includes fields from all currently entered spans, after
  +/// the event's fields. Span fields are not grouped by span, and span names are
  +/// not shown. In addition, a more compact representation of each event's
  +/// [`Level`](tracing::Level) is used.
  #[derive(Default, Debug, Copy, Clone, Eq, PartialEq)]
  pub struct Compact;
  -/// Marker for `Format` that indicates that the verbose log format should be used.
  +/// Marker for `Format` that indicates that the default log format should be used.
  ///
  -/// The full format includes fields from all entered spans.
  +/// This format shows the span context before printing event data. Spans are
  +/// displayed including their names and fields.
  #[derive(Default, Debug, Copy, Clone, Eq, PartialEq)]
  pub struct Full;
  