Install libghc-categories-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libghc-categories-doc
Description:
categories from category-extras; documentation
categories from category-extras. . This package provides the documentation for a library for the Haskell programming language. See http://www.haskell.org/ for more information on Haskell.
Homepage: http://github.com/ekmett/categories
Version: 1.0.7-6build2
Section: universe/doc