Change RLBot v5 status to pre-release

Updated the status of RLBot v5 from beta to pre-release and improved sentence structure.

Author: NicEastvillage

docs/v4/index.md

@@ -1,11 +1,11 @@
 # Overview
 
-!!! tip "RLBot v5 is in beta!"
+!!! tip "RLBot v5 is in pre-release!"
 	Learn more about v5 in the [RLBot v5 Overview](/v5/framework/v5) and start converting your bot today!
 
 Welcome to the RLBot wiki!
 RLBot is a framework for creating offline Rocket League bots.
-The framework uses an official Psyonix API making our bots safe to play with and against.
+The framework uses an official Psyonix API, making our bots safe to play with and against.
 This wiki primarily houses resources for bot development, but you can also find guides for users, framework documentation, and community insights.
 
 ## Getting Started