Update README.md

[d4rkr0n1n]

Tried something new, let me know if it's ok

[hamvocke]

Thanks, @d4rkr0n1n. I appreciate the effort, and the mermaid diagram works somewhat well as a replacement for this particular diagram :)

After thinking about this for a bit, I came to the conclusion that I prefer keeping it the way it was before, mostly for three reasons:

1. I've grown fond of the lo-fi ASCII diagrams over the years
2. The ASCII version works fine on local machines, without relying on GitHub's mermaid rendering
3. I like consistency - we can replace the diagram you replaced with a mermaid version, but the rest of the doc will use ASCII diagrams still

Thanks again for your contribution and putting thoughts into this :)