Install flycheck-doc by entering the following commands in the terminal:
sudo apt update sudo apt install flycheck-doc
Description:
modern on-the-fly syntax checking for Emacs - documentation
Flycheck uses various syntax checking and linting tools to automatically check the contents of buffers while the user types, and reports warnings and errors directly in the buffer, or in an optional error list. . This package includes flycheck's HTML documentation.
Homepage: http://flycheck.org/
Version: 31-1
Section: universe/doc