Refactor model selection logic for PR tools and update turbo model to…

… gpt-4o

README.md

@@ -42,7 +42,7 @@ CodiumAI PR-Agent aims to help efficiently review and handle pull requests, by p
 ## News and Updates
 
 ### May 19, 2024
-GPT-4o is now the default fast model ("Turbo"). This model will be used for all command except `review` and `improve`, which will still use "GPT-4-2024-04-09", since they are harder and would still benefit from the larger model.
+GPT-4o is now the default fast model ("Turbo"). This model will be used for all commands except `review` and `improve`, which will still use "GPT-4-2024-04-09", since they are harder and would still benefit from the larger model.
 
 ### May 12, 2024
 Inspired by [AlphaCodium](https://github.com/Codium-ai/AlphaCodium) flow engineering scheme, PR-Agent now performs **self-reflection** on the code suggestions it provides,