Add rich type webhook docs

Author: mpiot

notifier/chatters.rst

@@ -99,3 +99,56 @@ some interactive options called `Block elements`_::
     $chatter->send($chatMessage);
 
 .. _`Block elements`: https://api.slack.com/reference/block-kit/block-elements
+
+Adding Interactions to a Discord Message
+--------------------------------------
+
+With a Discord message, you can use the
+:class:`Symfony\\Component\\Notifier\\Bridge\\Discord\\DiscordOptions` to add
+some interactive options called `Embed elements`_::
+
+    use Symfony\Component\Notifier\Bridge\Discord\Block\DiscordEmbed;
+    use Symfony\Component\Notifier\Bridge\Discord\Block\DiscordFieldEmbedObject;
+    use Symfony\Component\Notifier\Bridge\Discord\Block\DiscordFooterEmbedObject;
+    use Symfony\Component\Notifier\Bridge\Discord\Block\DiscordMediaEmbedObject;
+    use Symfony\Component\Notifier\Bridge\Discord\DiscordOptions;
+    use Symfony\Component\Notifier\Message\ChatMessage;
+
+    $chatMessage = new ChatMessage('');
+
+    // Create Discord Embed
+    $discordOptions = (new DiscordOptions())
+        ->username('connor bot')
+        ->addEmbed((new DiscordEmbed())
+            ->color(2021216)
+            ->title('New song added!')
+            ->thumbnail((new DiscordMediaEmbedObject())
+            ->url('https://i.scdn.co/image/ab67616d0000b2735eb27502aa5cb1b4c9db426b'))
+            ->addField((new DiscordFieldEmbedObject())
+                ->name('Track')
+                ->value('[Common Ground](https://open.spotify.com/track/36TYfGWUhIRlVjM8TxGUK6)')
+                ->inline(true)
+            )
+            ->addField((new DiscordFieldEmbedObject())
+                ->name('Artist')
+                ->value('Alasdair Fraser')
+                ->inline(true)
+            )
+            ->addField((new DiscordFieldEmbedObject())
+                ->name('Album')
+                ->value('Dawn Dance')
+                ->inline(true)
+            )
+            ->footer((new DiscordFooterEmbedObject())
+                ->text('Added ...')
+                ->iconUrl('https://upload.wikimedia.org/wikipedia/commons/thumb/1/19/Spotify_logo_without_text.svg/200px-Spotify_logo_without_text.svg.png')
+            )
+        )
+    ;
+
+    // Add the custom options to the chat message and send the message
+    $chatMessage->options($discordOptions);
+
+    $chatter->send($chatMessage);
+
+.. _`Embed elements`: https://discord.com/developers/docs/resources/webhook