No point in showing an apologetic tab for a blob of binary data.
gtk4-demo shows the resources under /DEMONAME/ for each demo,
so move the data to /DEMONAME_data/.
Move the Unicode names to a separate source file,
and only build the demo if we have harfbuzz (since
we use script names, and those are only available
with harfbuzz).
Also, fix a forgotten type name.