Broken markdown display in scaladoc

[jchyb]

Compiler version

3.4.0-RC1-bin-20230901-89e8dba-NIGHTLY

Problem

Markdown display or parser is broken in nightly Scaladoc. This makes some parts hard to read, like the reflectModule (Mostly the fact that the type hierarchy is not shown as a code snippet)

Expectation

For reference, this is what it should look like: here

[nicolasstucki]

Is the ```none still supported? It is the only instance of this in the stdlib. We also have a few in the compiler.

https://github.com/lampepfl/dotty/blob/main/library/src/scala/quoted/Quotes.scala#L130

[jchyb]

The issue seems unrelated to none, and also happens in other places (like in the newVal/newClass example usage sections https://dotty.epfl.ch/api/scala/quoted/Quotes$reflectModule$SymbolModule.html)