No syntax highlighting inside language injections?

[daniel-noland]

So far as I can tell, there is no way to enable syntax highlighting in markdown code fences of type plantuml or puml.

For instance, the following in a markdown file does not highlight.

```puml
@startuml
Hello -> World
@enduml 
```

On the other hand, every other language I commonly use is highlighted as expected within code fences.

For example,

```rust
fn main() {}
```

displays as expected

Syntax highlighting works as expected in .puml files.

It is also worth noting that the in-editor preview and refactor functions work as expected inside code fences.

Is it possible to enable syntax highlighting in language injected sections like this?

Screen cap from a markdown file:

Screen cap from a .puml file: