Azure Devops wikis have excellent (although not full support) for mermaid diagrams. One power user feature I like is the ability to add a hyperlink to graph nodes like so:

click NodeName “URL”

Been using it in Gitlab for a while, was rather surprised Github didn't support it when I pushed a repo there.

There was an outstanding feature request on their forum for quite some while so didn't hold my breath for this to be added but glad it has.