Previously, the max column width for the pretty-printer was 50, which caused
generated package definitions to include unnecessary newlines, e.g.,
(home-page
"https://gitlab.com/ttyperacer/terminal-typeracer")
instead of
(home-page "https://gitlab.com/ttyperacer/terminal-typeracer")
* guix/scripts/import.scm (guix-import): Set max expression width to 80 when
pretty-printing.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>