extensions/configuration-editing/src/extensionsProposals.ts/provideWorkspaceTrustExtensionProposals
export function provideWorkspaceTrustExtensionProposals(existing: string[], range: vscode.Range): vscode.ProviderResult<vscode.CompletionItem[] | vscode.CompletionList> {
	if (Array.isArray(existing)) {
		const extensions = vscode.extensions.all.filter(e => e.packageJSON.main);
		const extensionProposals = extensions.filter(e => existing.indexOf(e.id) === -1);
		if (extensionProposals.length) {
			return extensionProposals.map(e => {
				const item = new vscode.CompletionItem(e.id);
				const insertText = `"${e.id}": {\n\t"supported": false,\n\t"version": "${e.packageJSON.version}"\n}`;
				item.kind = vscode.CompletionItemKind.Value;
				item.insertText = insertText;
				item.range = range;
				item.filterText = insertText;
				return item;
			});
		} else {
			const example = new vscode.CompletionItem(localize('exampleExtension', "Example"));
			example.insertText = '"vscode.csharp: {\n\t"supported": false,\n\t"version": "0.0.0"\n}`;"';
			example.kind = vscode.CompletionItemKind.Value;
			example.range = range;
			return [example];
		}
	}

	return undefined;
}