@ToddAndMargo, if you're still interested in having a builtin Raku file type, you can build a custom Geany from @techee's [PR][0], like this:
~~~sh [ ! -d geany ] && git clone -b perl6 https://github.com/techee/geany.git cd geany NOCONFIGURE=1 ./autogen.sh mkdir -p _build _build/share/geany/
pushd _build CFLAGS='-g -O0' \ ../configure --prefix=`pwd` \ --disable-html-docs \ --disable-pdf-docs \ --disable-api-docs \ --disable-gtkdoc-header \ --enable-binreloc=no make -j2 export LD_LIBRARY_PATH=`pwd`/src/.libs popd
cp -ru data/* _build/share/geany/ `pwd`/_build/src/.libs/geany -v ~~~
*Note* If you're on distribution that uses 'apt', you may need to run this first:
sudo apt install -y --no-install-recommends \ autopoint \ ccache \ gettext \ libtool \ libgtk-3-dev
[0]: https://github.com/geany/geany/pull/3169