fix W391 in modules, tests and rings

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with #34596, we are almost there

one file in rings is left aside for the moment

Component: **refactoring**

Author: **Frédéric Chapoton**

Branch/Commit: **[`d4eddec`](https://github.com/sagemath/sagetrac-mirror/commit/d4eddeceb082a2525d3dcacf09020ef444bf66c1)**

Reviewer: **Matthias Koeppe**

_Issue created by migration from https://trac.sagemath.org/ticket/34601_

