First example uses "graph" instead of "flowchart"

[victorp13]

Describe the bug
The first example uses "graph" instead of "flowchart"

To Reproduce
Link to Live Editor: https://mermaid-js.github.io/mermaid-live-editor/
Steps to reproduce the behavior:

1. It's the example loaded by default.

Expected behavior
I think the example should use "flowchart" instead of "graph"

[github-actions]

This issue is stale because it has been open 90 days with no activity. Remove stale label or comment or this will be closed in 14 days

[Macil]

I was very confused by this because the graph type doesn't support double-ended arrows, and it's not mentioned in the docs at all. It took me stupidly long to figure out I have to change graph to flowchart for the docs to actually match the live editor.

(Related issues: mermaid-js/mermaid#2772, mermaid-js/mermaid#2736)