Update metrics documentation

lib/src/client/config.dart

@@ -4,18 +4,27 @@ import 'package:meta/meta.dart';
 import 'package:spinify/src/model/pubspec.yaml.g.dart';
 
 /// Token used for authentication
+///
+/// {@category Client}
+/// {@category Entity}
 typedef SpinifyToken = String;
 
 /// Callback to get/refresh tokens
 /// This callback is used for initial connection
 /// and for refreshing expired tokens.
 ///
 /// If method returns null then connection will be established without token.
+///
+/// {@category Client}
+/// {@category Entity}
 typedef SpinifyTokenCallback = FutureOr<SpinifyToken?> Function();
 
 /// Callback to get initial connection payload data.
 ///
 /// If method returns null then no payload will be sent at connect time.
+///
+/// {@category Client}
+/// {@category Entity}
 typedef SpinifyConnectionPayloadCallback = FutureOr<List<int>?> Function();
 
 /// {@template spinify_config}

lib/src/model/metrics.dart

@@ -6,6 +6,9 @@ import 'package:spinify/src/client/state.dart';
 /// - unsubscribed
 /// - subscribing
 /// - subscribed
+///
+/// {@category Metrics}
+/// {@category Entity}
 typedef SpinifySubscriptionCount = ({
   int total,
   int unsubscribed,
@@ -16,7 +19,8 @@ typedef SpinifySubscriptionCount = ({
 /// {@template metrics}
 /// Metrics of Spinify client.
 /// {@endtemplate}
-/// {@category Client}
+///
+/// {@category Metrics}
 /// {@category Entity}
 @immutable
 final class SpinifyMetrics implements Comparable<SpinifyMetrics> {