Why isn't my custom singleton script template working?

I've made my own script template for singletons and want it to appear here: http://i.imgur.com/2Xt5Zgj.png

I've put it in this location: http://i.imgur.com/palES22.png

No matter what "menu locator"(?) number I use, 80, 85, 82, nothing will make it appear within Unity. As instructed I've been restarting Unity every time, going as far to do a full PC restart to double check that wasn't the issue. I've tried 5.5.1f1, and a version of 5.4 and it doesn't work for either.

I showed this to my programmer friend who had done this recently for his 5.4 build and he couldn't work out the issue either, could this be a bug with Unity somehow?

I'll link the content of the script below, in-case that is messing it up.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class #SCRIPTNAME# : MonoBehaviour
 {
     public static #SCRIPTNAME# instance;
 
         #region Singleton Setup
         void Awake()
         {
             if (instance != null) Destroy(this);
             else instance = this;
         }
        #endregion
 }

Thanks in advance for any help you guys can provide. I originally made a thread for this b/c I didn't know to use Answers.

I've also done a quick sanity-check to make sure it compiles (just in case I had missed something somehow), and it does.