doc: update pre-commit hook instruction to point to checkstyle

Now that checkstyle runs git-secrets, it is a true superset of the
checks that our existing pre-commit hook is running. Since checkstyle is
actually what our CI is validating, let's just point the git pre-commit
hook instruction to checkstyle, instead of maintaining a separate set of
checks somewhere else.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

CONTRIBUTING.md

@@ -57,39 +57,19 @@ If you just want to receive feedback for a contribution proposal, open an “RFC
 ## Contribution Quality Standards
 
 Most quality and style standards are enforced automatically during integration
-testing. For ease of use you can setup a git pre-commit hook by running the
+testing. For ease of use you can set up a git pre-commit hook by running the
 following in the Firecracker root directory:
 
 ```
-cargo install rusty-hook
-rusty-hook init
+cat >> .git/hooks/pre-commit << EOF
+./tools/devtool checkstyle || exit 1
+EOF
 ```
 
-This project also has linters for Python and Markdown. These will be called by
-the pre-commit when you modify any Python and Markdown files. In order to make
-sure you are setup we recommend you install
-[poetry](https://python-poetry.org/docs/) and
-[pyenv](https://github.com/pyenv/pyenv?tab=readme-ov-file#installation).
-
-Poetry is used by this project and pyenv will help you make sure you have a
-Python version compatible with the poetry python project we use as part of
-`./tools/devctr`.
-
-Once you have these two installed you can run the following to install the dev
-container poetry project:
-
-```
-poetry -C ./tools/devctr install --no-root
-```
-
-Then, you can activate the poetry virtual environment by running:
-
-```
-poetry shell -C ./tools/devctr
-```
-
-Which you will need to do after modifying python or markdown files so that the
-pre-commit can finish successfully.
+This will automatically lint your Rust, markdown and python changes when running
+`git commit`, as well as running any other checks our CI validates as part of
+its 'Style' step. Most reported violations can be automatically fixed using
+`./tools/devtool fmt`.
 
 Your contribution needs to meet the following standards: