Add local markdown linting to Makefile to avoid CI delays

[Elia-Renzoni]

Hi team,
I've been working on some documentation updates and noticed that markdown linting only happens in the CI pipeline.
This means every time there's a small formatting issue (like multiple blank lines), I have to push, wait for the entire test pipeline to run, see the error, fix it locally, and push again.
It would be really helpful to have a way to lint markdown files locally before pushing, similar to how we can run make lint for Go code. This would save a lot of time.
I was thinking of adding something like:

make lint-md - to check markdown files
make lint-md-fix - to auto-fix common formatting issues

Both would use the same markdownlint configuration that's already defined in .github/workflows/markdown_config.json.

Would this be acceptable? The only dependency would be having markdownlint-cli installed (via npm), but we could make it optional or add a check that fails gracefully if it's not installed.
If this sounds good, I'd be happy to submit a PR implementing it. Let me know what you think!

[ngjaying]

Hi @Elia-Renzoni,

Thanks for the great suggestion! Adding local linting to avoid CI delays makes a lot of sense.

[Elia-Renzoni]

Great, I'll open a PR as soon as possible