Update lint configuration to use custom rules to improve VSCode plugin use.

[fabulousgk]

Based on the discussion at TheOdinProject/.github#23, I am opening a discussion here to discuss and research possible solutions.

Essentially, can we find a way to improve how we configure the linting setup so that the VSCode plugin also works for the file structure?

Essential links:
Plugin config: https://github.com/DavidAnson/vscode-markdownlint/tree/main?tab=readme-ov-file#configure
Possible solution: https://github.com/DavidAnson/vscode-markdownlint/tree/main?tab=readme-ov-file#markdownlintcustomrules