chore(docs): markdown and docs linter

[justinthelaw]

Describe what should be investigated or refactored

Markdown linting should be implemented in developer workflows via pre-commit, and within the GH CI workflow. This ensures consistent styling and less inconsistencies with markdown rendering.

Links to any relevant code

• GitHub action: https://github.com/DavidAnson/markdownlint-cli2-action
• Example pre-commit config: https://github.com/justinthelaw/uds-rke2/blob/main/.pre-commit-config.yaml

Additional context

N/A