Matthew Butterick ff4bda8ee3 add -demo suffix to test langs to avoid name collisions
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README.txt add -demo suffix to test langs to avoid name collisions
txtadv.rkt add -demo suffix to test langs to avoid name collisions
world.rkt add -demo suffix to test langs to avoid name collisions

README.txt

The "world.rkt" module is unchanged. The "txtadv.rkt" module has a new
"Simple type layer" section with compile time code, which is now used
in the macros if the "Macros for constructing and registering
elements" section.