Add Markdown documentation linting

[msteslov]

Fixes #1785.

Adds a Markdown linting job to the basic CI workflow using rumdl.

Testing:

• rumdl check --config .rumdl.toml --respect-gitignore --exclude 'build,**/build' .
• actionlint -shellcheck "" .github/workflows/basic.yml

• Does this PR change the input/output behaviour of a cryptographic algorithm (i.e., does it change known answer test values)? (If so, a version bump will be required from x.y.z to x.(y+1).0.)
• Does this PR change the list of algorithms available -- either adding, removing, or renaming? Does this PR otherwise change an API? (If so, PRs in fully supported downstream projects dependent on these, i.e., oqs-provider will also need to be ready for review and merge by the time this is merged. Also, make sure to update the list of algorithms in the continuous benchmarking files: .github/workflows/kem-bench.yml and sig-bench.yml)

AI assistance was used for repository inspection and drafting; I reviewed and verified the final changes.

[xuganyu96]

LGTM. Thank you for the contribution.

[coveralls]

coverage: 82.297% (+0.006%) from 82.291% — msteslov:add-markdown-linter into open-quantum-safe:main

[xuganyu96]

I am sorry to have to walk back on my previous approval. The code change makes sense to me, but the choice of tool could use some justification. I did a quick search and found other markdown linters written in Ruby (markdownlint), Python (pymarkdown), and Rust (rumdl), and many others. It feels a tiny bit uncomfortable to introduce NPM into dev dependencies. I intuitively prefer keeping dev dependencies either in the Python ecosystem or as small binaries. Of course if markdownlint-cli is indeed a much more mature project than the other choices, then I am okay with introducing it into liboqs.

[msteslov]

Updated the PR to avoid the NPM dependency: it now uses rumdl==0.2.4 installed via Python/PyPI in CI, with a narrow .rumdl.toml rule set that passes on the existing documentation without unrelated Markdown churn. I also reduced the PR scope to only the workflow and linter configuration files.

[xuganyu96]

Thank you for the contribution. LGTM pending the GitHub Actions results.

[xuganyu96]

Hi, sorry for the late review and for walking back my approval again. It would great if you can address GitHub security bot's suggestions. Here is a script you can run to get the hashes.

wget https://files.pythonhosted.org/packages/c6/aa/d49dffee785b9004107042085d17fa010f455306817f033c0990b4abd3bc/rumdl-0.2.18-py3-none-win_amd64.whl
wget https://files.pythonhosted.org/packages/25/9d/25b76cd9fad8c8b070b97a21f01562911663cf7b4ed9238acaccfe61dd80/rumdl-0.2.18-py3-none-musllinux_1_2_x86_64.whl
wget https://files.pythonhosted.org/packages/51/6c/7ade7138bca98ab306554c5d9e6e6f135c839fe14dcb79809d8dd7eb8eaa/rumdl-0.2.18-py3-none-musllinux_1_2_aarch64.whl
wget https://files.pythonhosted.org/packages/1d/23/86a1cb7c274b41f09fe5e921ee8317d355a575b7476b577284c5ed33ee63/rumdl-0.2.18-py3-none-manylinux_2_28_x86_64.whl
wget https://files.pythonhosted.org/packages/05/9d/21697889a192fa8c0b5ad4832f43a5a94699fb5da8f81ce7a72cec60b893/rumdl-0.2.18-py3-none-manylinux_2_28_aarch64.whl
wget https://files.pythonhosted.org/packages/ae/59/ab5be3d6494c55ca2d2beda516f8fb69e5db84e3cf5d114fcdbd78593389/rumdl-0.2.18-py3-none-macosx_11_0_arm64.whl
wget https://files.pythonhosted.org/packages/8f/0f/35d32954432cbe7bbfd5613e9eca6f41cb6d05373d81efd662e690ab2ed2/rumdl-0.2.18-py3-none-macosx_10_12_x86_64.whl

pip hash *.whl