There's a merged pull request on the void-packages repository

python3-sympy: update to 1.12.
https://github.com/void-linux/void-packages/pull/43842

Description:
#### Testing the changes
- I tested the changes in this PR: **briefly**

Works fine with sagemath. A few tests need to be fixed as in https://github.com/sagemath/sage/pull/35635 but it's all cosmetic, nothing critical, so this can be merged just fine. We will fix those dooctests when the next release of sagemath is ready (10.0, prerelease in #43659).

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