Usage example

# Run mypy against the Python code blocks in README.md and CHANGELOG.rst
$ doccmd --language=python --command="mypy" README.md CHANGELOG.rst

# Run gofmt against the Go code blocks in README.md
# This will modify the README.md file in place
$ doccmd --language=go --command="gofmt -w" README.md

# or type less... and search for files in the docs directory
$ doccmd -l python -c mypy README.md docs/

# Run ruff format against the code blocks in a Markdown file
# Don't "pad" the code blocks with newlines - the formatter wouldn't like that.
# See the documentation about groups for more information.
$ doccmd --language=python --no-pad-file --no-pad-groups --command="ruff format" README.md

# Run j2lint against the sphinx-jinja2 code blocks in a MyST file
$ doccmd --sphinx-jinja2 --no-pad-file --no-pad-groups --command="j2lint" README.md