Fix arg parse on server start

src/index.js

@@ -83,10 +83,11 @@ function setupLanguageServer(ws, server, workspace) {
 
 function startLanguageServer(languageServer, workspace) {
     const env  = process.env;
-    const args = languageServer.args.map(arg =>
+    const args = languageServer.args.flat().map(arg =>
         typeof arg === 'string' ? arg.replace('{workspace.path}', workspace || '') : arg
     ).filter(arg => arg !== '');
-    const serverProcess = spawn(...args, {env, shell: true});
+
+    const serverProcess = spawn(args[0], args.slice(1), { env, shell: true });
 
     serverProcess.stderr.on('data', data => {
         console.error(`${serverProcess.spawnfile} error: ${data}`);