except in the designs/ and matrices/ subfolders of combinat

done using autopep8 -i --select=E3 *.py

CC: @tscrim @kwankyu @mantepse

Component: combinatorics

Author: Frédéric Chapoton

Branch/Commit: c29eb40

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/34910