make more similar to reference example

src/extension.ts

@@ -25,6 +25,8 @@ export function executableExists(exe: string): boolean {
   return out.status === 0 || (isWindows && fs.existsSync(exe));
 }
 
+let client: LanguageClient;
+
 export function activate(context: ExtensionContext) {
 
 	if (executableExists('vhdl-tool')) {
@@ -46,13 +48,21 @@ export function activate(context: ExtensionContext) {
 		}
 		
 		// Create the language client and start the client.
-		let disposable = new LanguageClient('vhdltool', 'Language Server VHDL', serverOptions, clientOptions).start();
+		let client = new LanguageClient('vhdltool', 'Language Server VHDL', serverOptions, clientOptions);
 		
 		// Push the disposable to the context's subscriptions so that the client can be deactivated on extension deactivation
-		context.subscriptions.push(disposable);
+		client.start();
 	} else {
 		const notInstalledMsg: string =
 			'Please download VHDL-Tool from https://www.vhdltool.com/download and place it somewhere in your $PATH';
 		window.showErrorMessage(notInstalledMsg);
 	}
 }
+
+export function deactivate(): Thenable<void> | undefined {
+	if (!client) {
+		return undefined;
+	}
+	return client.stop();
+}
+