themes: Avoid ':' in custom target names
For whatever reason, meson decides to use custom target names in the file system, and on Windows, the ':' is causing trouble here. So avoid it.
Fixes: #5280 (closed)
For whatever reason, meson decides to use custom target names in the file system, and on Windows, the ':' is causing trouble here. So avoid it.
Fixes: #5280 (closed)