Add remark-emoji

[mkloubert]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and discussions and couldn’t find anything or linked relevant results below
• I made sure the docs are up to date
• I included tests (or that’s not needed)

Description of changes

Add remark-emoji

[JounQin]

Seems duplicated of with https://github.com/remarkjs/remark-gemoji?

[wooorm]

Hi! It’s a nice plugin, and it’s in the list of plugins. But this list isn’t for all nice plugins. It’s a shortlist of cool examples. So, thank you, but no thank you!