[documentation] emojis

[cassgvp]

• [ ] Check that emojis currently used are rendered on different browsers and operating systems
• [ ] add emoji Jekyll plug-in?
• [ ] Use emojis of all skin tones for open documentation as recommended here

[cassgvp]

This guide to a GitHub emojis plugin looks useful https://docs.github.com/en/enterprise/2.14/user/articles/emoji-on-github-pages