Add information about line numbering and line highlighting into documentation

[talatkuyuk]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)
• If applicable, I’ve added docs and tests

Description of changes

It is about for adding information about line numbering and line highlighting into documentation, which is done via rehype plugin rehype-highlight-code-lines. An example has been provided as well.

Fixes #29

[wooorm]

Hi again Talat, thanks for your patience, I was a bit busy. I took your take as inspiration and wrote a short example in the existing example section! Thank you.

Also: looks like the email you git commit with isn’t connected to your GitHub account; I think they describe how to add an email address here: https://docs.github.com/en/account-and-profile/setting-up-and-managing-your-personal-account-on-github/managing-email-preferences/setting-your-commit-email-address.

Or, perhaps, you accidentally added literal quotes locally in Git itself? 🤔

Finally, for your plugin:
your plugin supports a markdown syntax on how to highlight particular lines. That’s very useful!
But, these rehype plugins can also be used with plain HTML. So, I suggest to also support HTML attributes.
I’ve done something similar with rehype-twoslash recently, which accepts ```js twoslash but also class="language-js twoslash".