docs update

Author: MaximilianB2

docs/index.md

@@ -88,7 +88,7 @@ pip install git+https://github.com/MaximilianB2/pc-gym
 Example notebooks with training walkthroughs, implementing constraints, disturbances and the policy evaluation tool can be found [here](https://github.com/MaximilianB2/pc-gym/tree/main/example_notebooks).
 
 ## Environments 
-Currently there are three implemented process control environments, this will be expanded to 10 prior to full release.
+Currently there are six implemented process control environments, this will be expanded over time.
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