solve warinings and remove legacy packages

[caioishikawa]

This pull request makes several improvements to documentation, project configuration, and code comments for clarity and modernization. The most significant changes include migrating the documentation system from reStructuredText (RST) to Markdown (MD) using MyST, updating the project configuration to the modern PEP 621 pyproject.toml format, and cleaning up or removing outdated documentation files and code. Below are the most important changes grouped by theme:

Documentation System Modernization:

• Migrated Sphinx documentation from RST to Markdown using the MyST parser, replacing recommonmark and nbsphinx with myst-parser, and removing old Markdown-to-RST conversion logic from conf.py and build_release_notes.py. The documentation build now directly supports .md files, and the contributing guide and release notes are handled as Markdown. [1] [2] [3] [4] [5]

• Updated and improved formatting in multiple documentation files for clarity and consistency, such as fixing section underlines, code block formatting, and clarifying docstrings and usage notes. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

Project Configuration Updates:

• Migrated from Poetry's old [tool.poetry] format to the PEP 621 [project] section in pyproject.toml, explicitly listing dependencies, scripts, and optional documentation dependencies. Python version requirement is now >=3.11,<3.13. [1] [2]

Documentation Cleanup and Removal:

• Removed the obsolete docs/source/developer/corrections.rst and the strax.corrections API documentation section from the reference docs, likely due to outdated or redundant content. [1] [2]

Contribution Guidelines Update:

• Improved the formatting and structure of CONTRIBUTING.md for readability, using proper Markdown heading levels. [1] [2] [3]

Other Minor Improvements:

• Set the Sphinx documentation language to English explicitly.

These changes collectively modernize the documentation workflow, clarify contribution and usage instructions, and update project configuration for better maintainability and clarity.