Remove old guides

documentation/docs/messaging.md

@@ -1,11 +1,5 @@
 # Messaging
 
-!!! warning
-
-    If you are using Rinf version 5 or earlier, please refer to the [historical documentation](https://github.com/cunarist/rinf/blob/v5.4.0/documentation/docs/writing-code.md). With the introduction of Rinf version 6, a simpler way for communication between Dart and Rust has been implemented, and the system has undergone significant changes.
-
-Marking Protobuf messages with special comments empower them with the capability to transmit signals across Dart and Rust. This is achieved by allowing Rinf's code generator to create the necessary channels for communication between Dart and Rust.
-
 There are 2 types of special comments that you can mark messages with.
 
 ## 📭 Dart Signal