Support curly braces for defining "chunk options" in fenced code blocks of markdown documents

[jdidion]

Rmarkdown (http://rmarkdown.rstudio.com/) enables creation of reproducible documents using R. The main deviation of Rmarkdown from CommonMark is the use of curly braces in the header of fenced code blocks to define options related to the rendering of the figure/table described in the chunk. It would be nice if VS Code does proper syntax highlighting of code blocks in Rmarkdown documents.

• VSCode Version: 1.1.3

Example code block:

```{r include=FALSE, pdf.width=100px}
ggplot(foo, aes(x=bar, y=baz)) + geom_boxplot()
```

[mjbvz]

There are two parts to this:

• Syntax highlighting of the codeblock in the editor
• Correct rendering of the fenced code block in the markdown preview

I believe that both components should come from an extension rather than the core markdown extension.

For the syntax highlighting, take a look at https://github.com/mjbvz/vscode-fenced-code-block-grammar-injection-example

For the preview rendering, take a look at #22916

[vscodebot]

We try to keep VS Code lean and we think the functionality you're asking for is great for a VS Code extension. Maybe you can already find one that suits you in the VS Code Marketplace. Just in case, in a few simple steps you can get started writing your own extension. See also our issue reporting guidelines.

Happy Coding!