chore(docs): remove reference to rye shell

Author: stainless-app[bot]

CONTRIBUTING.md

@@ -17,8 +17,7 @@ $ rye sync --all-features
 You can then run scripts using `rye run python script.py` or by activating the virtual environment:
 
 ```sh
-$ rye shell
-# or manually activate - https://docs.python.org/3/library/venv.html#how-venvs-work
+# Activate the virtual environment - https://docs.python.org/3/library/venv.html#how-venvs-work
 $ source .venv/bin/activate
 
 # now you can omit the `rye run` prefix