extensions/typescript-language-features/src/typeScriptServiceClientHost.ts/TypeScriptServiceClientHost/findLanguage
class TypeScriptServiceClientHost:	private async findLanguage(resource: vscode.Uri): Promise<LanguageProvider | undefined> {
		try {
			const doc = await vscode.workspace.openTextDocument(resource);
			return this.languages.find(language => language.handles(resource, doc));
		} catch {
			return undefined;
		}
	}