Azurite:
When I look at the actual template (http://www.seventh-star.net/wikific/index.php/Template:Endspoiler),
it
looks fine-- it includes the documentation I added and everything. But there's a link to that template "template doc page transcluded" which
I
guess isn't a default of MediaWiki, so it wants to be created.
What you're dealing with here is nothing to do with MediaWiki itself -- this "template doc page transcluded" stuff is all part of some conventional structure that the Wikipedia people use to organise and document their templates.
I'm guessing that you copied that template in from Wikipedia? I can't view the source, so it's hard to tell. But basically your template includes an invocation of a template called "Template:Template doc page transcluded", which doesn't exist in your Wiki. On Wikipedia, as far as I can tell, that template is just a notice which is part of how Wikipedia handles its templates. (They create a sub-page called "Template:xxx/doc" to hold the documentation for a template xxx.)
If you want to copy the whole Wikipedia template strategy, then you'll need that template, and probably a bunch of other stuff. Personally, I wouldn't bother; just cut out the {{Template:Template doc page transcluded}} call from your template.
Ian