fix: add ref() and unref() to chokidar.d.ts for typescript build to work (#15706)

Author: saerich

packages/vite/src/node/watch.ts

@@ -45,6 +45,14 @@ class NoopWatcher extends EventEmitter implements FSWatcher {
     return {}
   }
 
+  ref() {
+    return this
+  }
+
+  unref() {
+    return this
+  }
+
   async close() {
     // noop
   }

packages/vite/src/types/chokidar.d.ts

@@ -40,6 +40,19 @@ export class FSWatcher extends EventEmitter implements fs.FSWatcher {
    */
   constructor(options?: WatchOptions)
 
+  /**
+   * When called, requests that the Node.js event loop not exit so long as the fs.FSWatcher is active.
+   * Calling watcher.ref() multiple times will have no effect.
+   */
+  ref(): this
+
+  /**
+   * When called, the active fs.FSWatcher object will not require the Node.js event loop to remain active.
+   * If there is no other activity keeping the event loop running, the process may exit before the fs.FSWatcher object's callback is invoked.
+   * Calling watcher.unref() multiple times will have no effect.
+   */
+  unref(): this
+
   /**
    * Add files, directories, or glob patterns for tracking. Takes an array of strings or just one
    * string.