doc: update contributing guidelines wrt pre-commit/devtool

Point external contributors to use devtool instead
of unmaintained pre-commit script to check code
quality/style.

Signed-off-by: Dakshin Devanand <[email protected]>

Author: DakshinD

CONTRIBUTING.md

@@ -57,39 +57,23 @@ 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
-following in the Firecracker root directory:
+testing. To run these quality and style checks, use `devtool`.
 
-```
-cargo install rusty-hook
-rusty-hook init
-```
-
-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:
+```bash
+# Format code (Rust, Python, Markdown)
+./tools/devtool fmt
 
+# Check code style and lint warnings
+./tools/devtool checkstyle
 ```
-poetry -C ./tools/devctr install --no-root
-```
-
-Then, you can activate the poetry virtual environment by running:
 
-```
-poetry shell -C ./tools/devctr
-```
+Refer to [docs/getting-started.md](docs/getting-started.md) and run
+`tools/devtool --help` for more information on `devtool`, such as build
+verification, tests, etc.
 
-Which you will need to do after modifying python or markdown files so that the
-pre-commit can finish successfully.
+> **Note:** The legacy rusty-hook pre-commit script has been deprecated and is
+> unmaintained. Please use `devtool` for formatting, linting, and build checks
+> during your development cycle.
 
 Your contribution needs to meet the following standards: