Use the display format defined by plugins

src/main/java/net/minecraft/server/NetServerHandler.java

@@ -432,7 +432,7 @@ implements ICommandListener {
             // CraftBukkit start
             PlayerChatEvent event = new PlayerChatEvent(Type.PLAYER_CHAT, player, s);
             server.getPluginManager().callEvent(event);
-            s = (new StringBuilder()).append("<").append(event.getPlayer().getDisplayName()).append("> ").append(event.getMessage()).toString();
+            s = String.format(event.getFormat(), event.getPlayer().getDisplayName(), event.getMessage());
             if (event.isCancelled()) return;
             // CraftBukkit stop