Quarto language detection for vscode

[silverhikari]

Issues

closes #3340

Description

this code adds "onLanguage:quarto" to the package.json to allow for suggestions when working in quarto documents using the official quarto extension

How Has This Been Tested?

i have tested the code by adding the line to pre-built extension's package.json and after adding it and restarting vscode, it was able to give suggestions when opening a document in quarto language mode

AI Disclosure

• I am a human and didn't use any AI.

Checklist

• I have performed a self-review of my own code

[mcecode]

LGTM.

Just know that we currently don't have any special handling for Quarto and simply treat it as Markdown:

harper/harper-ls/src/backend.rs

Line 396 in 491c441

"markdown" | "quarto" => Some(Box::new(Markdown::new(markdown_options))),

The OP in the PR (#3053) that added support mentioned that it should be fine, though our Markdown parser only more or less guarantees CommonMark compliance so you might see some breakages when using Quarto-specific syntax.