`julia` and `@example` blocks in markdown files are no longer runnable line-by-line

[franckgaga]

On Julia VS Code v1.231.1:

It's no longer possible to execute julia or @example code blocks of a md file in the Julia REPL line-by-line (with "Shift + Enter").

These commands no longer work in a Markdown file:

• Julia: Execute Code in the REPL ("Ctrl + Enter")
• Julia: Execute Code in the REPL and Move ("Shift + Enter")

These commands still work in a Markdown file:

• Julia: Execute File in the REPL
• Julia: Execute Code Cell in the REPL ("Alt + Enter")
• Julia: Execute Code Cell in the REPL and Move ("Shift + Alt + Enter")

The commands that no longer work print the block with backticks instead of running it:

Here's a MRE:

# My Markdown File

asdasd

```julia
a  = 2
a2 = 3
```

asdasd

```julia
b = 3
```

```@example 1
c= 3
```

[davidanthoff]

I think we lost support for markdown files in the transition to JW... Should be added back for sure.