Updated dependency and, with its newly provided type hints, removed some
pyright overrides.
Added a cast where there was still not enough type hinting.
It relies on the libmagic module which is not necessarily installed
everywhere. Most of the functionality that we need for our purposes can
be recreated with lighter-weight methods.
The complete read routine would work before figuring out that it is
a file of xml mimetype. This means that it would try to read to memory
any file as the first thing, pdfs, even binaries. Of course doing
so crashed the program.
