Implement "Other Element" in demo

[herbhuang]

Hello, I tried to implement the other element syntax in your demo

Specifically, I tried to use abbr in my .md content. However, I am not sure of the correct syntax and I cannot see the source code of your demo website.

Could you provide the source code or a line of code to write "abbr, sub, sup, kbd, mark" in .md file 😄