/usr/lib/ghc-doc/hoogle/fsnotify.txt is in libghc-fsnotify-doc 0.0.11-2build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-fsnotify-doc/html/fsnotify.txt