docs(devguide)📝: revise and streamline development guide for contributors

- Rewrite devguide.md to provide a clearer, step-by-step guide for setting up the development environment and contributing to pyjanitor.
- Emphasize use of pixi for environment management and pre-commit hooks.
- Clarify branch management, testing, and documentation preview steps.
- Add tips for running specific tests and viewing documentation locally.
- Update compatibility and help sections for new contributors.
- Update pixi.lock due to changes in the local package hash.
- Add a 'start' task to pixi tasks in pyproject.toml to install pre-commit hooks.

Author: ericmjl