The `node16` module resolution requires imports to use the `.js` file
extension in type definitions.
`@rollup/plugin-typescript` is needed to make this work with the Vite
setup used by Mermaid.
The module option for Mermaid internally is set to `nodenext`. This is
needed to support `.json` imports. Note that setting `module` to
`node16` or `nodenext` implies a matching `moduleResolution` value.
The if-check for arrowMarkerAbsolute in the flowchart-v2 code is in
dagre-wrapper. Unfortunately, I can't seem to find a way to find the
local conf (e.g. the one set via `flowRenderer.setConf()`, so instead
I'm using global mermaid config from `src/config`.
Flowchart v1 arrowMarkerAbsolute=true is still broken, but I'm not
really sure how to fix that.
