added documentation for deriving textchatmessageproperties

Author: foshesss

content/en-us/reference/engine/classes/TextChatMessageProperties.yaml

@@ -11,6 +11,23 @@ description: |
   defined in `Class.TextChatService.OnIncomingMessage` or
   `Class.TextChannel.OnIncomingMessage`. This can be used to customize the
   appearance of a message with [rich text](../../../ui/rich-text.md) tags.
+
+  ```lua title='LocalScript - Retrieving and Using TextChatMessageProperties'
+  local TextChatService = game:GetService("TextChatService")
+  TextChatService.OnIncomingMessage = function(message: TextChatMessage)
+    -- deriving TextChatMessageProperties
+    local properties = TextChatService.ChatWindowConfiguration:DeriveNewMessageProperties()
+    
+    -- changing color of messsage
+    properties.TextColor3 = Color3.fromRGB(255, 121, 121)
+    
+    -- setting message's chatwindowmessageproperties
+    message.ChatWindowMessageProperties = properties
+
+    return properties	
+  end
+  ```
+
 code_samples: []
 inherits:
   - Instance