This ticket arises from #19895 and implements the following parts:

• Simplify code in __repr__ and allow customization.

• Minor improvement of documentation

• A couple of smaller bug fixes (correcting/updating the parameter stop when using slices)

• Various smaller code improvements and simplifications.

CC: @mantepse @videlec

Component: misc

Author: Daniel Krenn

Branch/Commit: 18e1348

Reviewer: Vincent Delecroix

Issue created by migration from https://trac.sagemath.org/ticket/21164