In Fedora 39, the "freetype-devel" package is now a dependency

[pdelong42]

Small but significant update to the documentation:

When I attempted to run pip install rmfuse on my Fedora 39 image, it failed when it couldn't find ft2build.h. After some digging around, I found that it's part of the freetype-devel package.

The "Fedora-based systems" heading in README.md ought to be updated to include this. I'll submit a pull-req with the change if I get a moment, but I figure it's probably best to track it with an issue, in case someone else beats me to it.