Documentation: we might return `bytearray` objects
Documentation: we might return `bytearray` objects

The pymad module didn't document this change, but it started returning
bytearray objects as of version 0.9:
https://github.com/jaqx0r/pymad/commit/0231d165dcc192e769b9480cbe5bc2586feb8fc1#comments

So we now might produce that type. See also beetbox/pyacoustid#31 and
beets/issues#2216.

beetbox/audioread