Remove Dart link

We no longer support or generate Dart reference documentation.

Bug: 357620464
Change-Id: I38472fc75d3a57a96b6310e6a9c1aef30f7c0686
Reviewed-on: https://fuchsia-review.googlesource.com/c/api-docs-resources/+/1184052
Reviewed-by: Paul Kirth <[email protected]>
1 file changed