/usr/lib/ghc-doc/hoogle/control-monad-loop.txt is in libghc-control-monad-loop-doc 0.1-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-control-monad-loop-doc/html/control-monad-loop.txt