add doc

lib/src/channel_name.dart

@@ -1,6 +1,9 @@
 import 'package:flutter/material.dart';
 import 'package:stream_chat/stream_chat.dart';
 
+/// It shows the current [Channel] name using a [Text] widget.
+///
+/// The widget uses a [StreamBuilder] to render the channel information image as soon as it updates.
 class ChannelName extends StatelessWidget {
   const ChannelName({
     Key key,
@@ -8,7 +11,10 @@ class ChannelName extends StatelessWidget {
     this.textStyle,
   }) : super(key: key);
 
+  /// The channel to show the name of
   final Channel channel;
+
+  /// The style of the text displayed
   final TextStyle textStyle;
 
   @override