Document markdown debug server build path (#223812)

For debugging, we may want to load the non-bundled path. Only useful when using `yarn link` for local development so just adding as comment

extensions/markdown-language-features/src/extension.ts

@@ -31,6 +31,8 @@ function startServer(context: vscode.ExtensionContext, parser: IMdParser): Promi
 
 	const serverModule = context.asAbsolutePath(
 		isDebugBuild
+			// For local non bundled version of vscode-markdown-languageserver
+			// ? './node_modules/vscode-markdown-languageserver/out/node/workerMain'
 			? './node_modules/vscode-markdown-languageserver/dist/node/workerMain'
 			: './dist/serverWorkerMain'
 	);