Update 12.22.2016 Since this has become quite a popular script, I've converted it into a Google Docs Add On so it can be used across documents. Check out the blog post or the Endnote Generator website for more information.
Update 8.27.2016 As Phil noted in the comments, the script didn't format anything over two digits in length. That has been corrected in the source. If you need more (100+ endnotes may be too many, though...) leave a comment and I'll go back and make the changes.
Krissy Venosdale asked on Tuesday if there was a way to make endnotes in Google Docs as easily as footnotes. I thought, "Surely there is."
Well, there's not.
So I wrote a script that does it.
It's hosted on GitHub along with instructions on how to install the script (it's not an add-on...just a custom script) and run it in your document.
Here's a peek:
When you add the script to the document (manual process right now - read the instructions) it adds a custom menu from which you run the script.
I know endnotes and footnotes aren't really used in high school, but if you're writing a book or something...maybe it'll be helpful to you.
Either way, it was fun to write and it works pretty quickly. I haven't tested it with documents more than a few pages long, so if you're going to try it on something major, I'd suggest making a duplicate copy to run it on first, just in case.
I'm a teacher by day, after all.