refactor(typescript): drop createAsyncLanguageServicePlugin API (#272)

Author: johnsoncodehk

packages/typescript/lib/node/proxyLanguageService.ts

@@ -44,7 +44,7 @@ const windowsPathReg = /\\/g;
  * Creates and returns a Proxy around the base TypeScript LanguageService.
  *
  * This is used by the Volar TypeScript Plugin (which can be created by `createLanguageServicePlugin`
- * and `createAsyncLanguageServicePlugin`) as an adapter layer between the TypeScript Language Service
+ * as an adapter layer between the TypeScript Language Service
  * plugin API (see https://github.com/microsoft/TypeScript/wiki/Writing-a-Language-Service-Plugin)
  * and a Volar `Language`.
  *

packages/typescript/lib/quickstart/createAsyncLanguageServicePlugin.ts

@@ -23,8 +23,6 @@ export function createLanguageServicePlugin(
 						.map(plugin => plugin.typescript?.extraFileExtensions.map(ext => '.' + ext.extension) ?? [])
 						.flat();
 
-					// TODO: this logic does not seem to appear in the async variant
-					// (createAsyncLanguageServicePlugin)... bug?
 					projectExternalFileExtensions.set(info.project, extensions);
 
 					const { proxy, initialize } = createProxyLanguageService(info.languageService);