Support multiple options for file extension matching.

diffoscope/comparators/apk.py

diffoscope/comparators/debian.py

diffoscope/comparators/debian_fallback.py

diffoscope/comparators/dex.py

diffoscope/comparators/fontconfig.py

diffoscope/comparators/gnumeric.py

diffoscope/comparators/gzip.py

diffoscope/comparators/ipk.py

diffoscope/comparators/javascript.py

diffoscope/comparators/lz4.py

diffoscope/comparators/openssl.py

diffoscope/comparators/pgp.py

diffoscope/comparators/ppu.py

diffoscope/comparators/rdata.py

diffoscope/comparators/rust.py

diffoscope/comparators/utils/file.py

diffoscope/comparators/wasm.py

diffoscope/comparators/xml.py

diffoscope/comparators/xsb.py

diffoscope/comparators/xz.py