/usr/lib/ghc-doc/hoogle/quickcheck-io.txt is in libghc-quickcheck-io-doc 0.1.0-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-quickcheck-io-doc/html/quickcheck-io.txt