Support for running nbqa on quatro format (.qmd) markdown files

[hguturu]

Closes #880

Two main changes:

• Added check for .qmd when using Jupytext
• Added conversion of leading quartro cell options #| that get changed to # | by black/ruff back to #|
  (_restore_quarto_cell_options) - in theory this can be dropped if black and ruff natively support this format
  • black is evaluating how to handle this situation - Exceptions to comment spacing psf/black#3668
  • ruff also has the issue - Add support for Quarto notebooks  astral-sh/ruff#6140
• Added test_jupytext.test_qmd and supporting resource tests/data/notebook_for_testing.qmd to test new functionality
• Updated README.md with .qmd support feature
• Updated requirements-dev.txt and setup.cfg with quarto-cli dependency