Tooltips for emoji in Diagram Syntax doc tree

[clhodapp]

Proposal

In the "Diagram Syntax" area of the documentation tree (visible on from anywhere in the docs), the team like to put emoji next to the names of various diagram types. However, there isn't any reference to discover the meaning of each of the icons. As a user, I still don't know the exact meaning of the icons, even after using Mermaid diagrams several times.

I propose adding tooltips to the emoji, so that it's actually possible for users to understand what information they are supposed to communicate.