language-tools: Style tag `lang` attribute triggers warning from Svelte Beta

Describe the bug When specifying a lang attribute in component’s <style> tag, Svelte Beta for VS Code gives the following warning:

The file cannot be parsed because script or style require a preprocessor that doesn't seem to be setup. Did you setup a `svelte.config.js`? See https://github.com/sveltejs/language-tools/tree/master/packages/svelte-vscode#using-with-preprocessors for more info.

This only happens when specifying the lang attribute on the component <style>. When the lang attribute is removed from the <style> tag, the warning goes away, regardless of if there is a lang attribute on the component <script> tag.

To Reproduce Steps to reproduce the behavior:

1. Create a new Svelte + Webpack project by using: degit svelte/template-webpack
2. Install TypeScript, Node Sass, and Svelte Preprocess: npm i -D typescript node-sass svelte-preprocess
3. Create a svelte.config.js:

const sveltePreprocess = require('svelte-preprocess')

module.exports = {
  preprocess: sveltePreprocess()
}

1. Restart Svelte Beta in VS Code
2. Add lang="scss" to <style> tag in src/App.svelte
3. Save file. Svelte Beta warning should appear on <script> tag

Expected behavior Expected Svelte Beta to not return any warnings or errors.

Screenshots

System:

• OS: Windows 10
• IDE: VSCode 1.45.0
• Plugin/Package: “Svelte Beta”

Additional context Frequently recommended/obvious fixes that did not work:

• Double, triple, and quadruple checked that I had a svelte.config.js file at the root of my project.
• Tried setting runtime to path to Node.js: C:\Program Files\nodejs\node.exe
• Tried the following variants of svelte.config.js:

const sveltePreprocess = require('svelte-preprocess')

module.exports = {
  preprocess: [sveltePreprocess()]
}

const sveltePreprocess = require('svelte-preprocess')

module.exports = {
  preprocess: sveltePreprocess({
    sass: true
  })
}

const sveltePreprocess = require('svelte-preprocess')

module.exports = {
  preprocess: sveltePreprocess({
    sass: true,
    typescript: true
  })
}

• Webpack configuration uses preprocess options exported by svelte.config.js and compiles Svelte code with no errors or warnings.