.markdownlint.yaml out of date

[JTorreG]

Describe the bug

https://github.com/nginxinc/docs/commits/main/.markdownlint.yaml

The markdownlint rule file does not represent the current style recommendations by the Docs team.

We should either reach some consensus on which rules we want to enforce, update it, and add the linter to our pipeline, or remove the (outdated) file.

As a contributor I expect the .markdownlint.yaml file to show the current guidance and linting rules for the NGINX documentation

[mjang]

I believe this issue extends to all F5 documentation. As suggested by @JTorreG on Slack, (and I agree) -- this is a two-fold conversation;

• on the writers side to decide which rules to enforce
• on the engineering side on what is the best way to implement it in our workflow

[JTorreG]

The discussion for rules started last week and we can continue it in a live conversation.

[ADubhlaoich]

I'm taking this over.

I added gitlint a while ago for enforcing conventional commits, and added it to precommit.

I want to add general Markdown linting to precommit, too.