Added ForwardingAudience support guide

resolves #11

Author: 4drian3d

docs/developer-guide/ForwardingAudience_Capability.md

@@ -0,0 +1,41 @@
+---
+title: ForwardingAudience Support
+sidebar_label: 'ForwardingAudience Support'
+sidebar_position: 7
+---
+
+There are some cases where it is necessary to use Audience Wrappers, especially in the case of cross-platform plugins.
+
+For this reason, MiniPlaceholders supports Audience wrappers that implement the ForwardingAudience.Single interface.
+
+```java
+public record AudienceWrapper(Player player) implements ForwardingAudience.Single {
+    @Override
+    public Audience audience() {
+        return this.player;
+    }
+}
+```
+
+For example, here we create a wrapper that contains a player. In a real situation, this class would have much more logic, but for this example, we will create a basic wrapper.
+
+Having created the wrapper, we can also use it to obtain placeholders for the player contained within the wrapper.
+
+```java
+final Player player = event.getPlayer();
+final AudienceWrapper wrapperAudience = new AudienceWrapper(player);
+final TagResolver resolver = MiniPlaceholders.audiencePlaceholders();
+final Component parsedMessage = MiniMessage.miniMessage().deserialize("Player Name: <player_name>", wrapperAudience, resolver);
+```
+
+Note that this will only work if the expansion that will provide the placeholders correctly declares its preferred audience type.
+
+
+```java
+Expansion.builder("test")
+    .audiencePlaceholder(Player.class, "placeholder", (player, ctx, queue) -> {
+        return Tag.preProcessParsed(player.getName());
+    });
+```
+
+To use this feature, you can refer to plugins that already use this feature continuously, such as [CarbonChat](https://github.com/Hexaoxide/Carbon).