This special tag is similar to the [[harlowe:startup]] tag, but only causes the passage
to be included if you're running the story in debug mode.

This has a variety of uses: you can put special debugging code into this
passage, or set up a late game state to test, and have that code run
whenever you use debug mode, no matter which passage you choose to test.

All passages tagged with ''%%debug-startup%%'' will run, in alphabetical order
by their passage name, after the passages tagged ''%%startup%%'' will run.