extensions/configuration-editing/src/settingsDocumentHelper.ts/SettingsDocument/provideLanguageCompletionItemsForLanguageOverrides
class SettingsDocument:	private async provideLanguageCompletionItemsForLanguageOverrides(_location: Location, range: vscode.Range): Promise<vscode.CompletionItem[]> {
		const languages = await vscode.languages.getLanguages();
		const completionItems = [];
		for (const language of languages) {
			const item = new vscode.CompletionItem(JSON.stringify(language));
			item.kind = vscode.CompletionItemKind.Property;
			item.range = range;
			completionItems.push(item);
		}
		return completionItems;
	}