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

python3-ipython: fix broken matplotlib_inline import
https://github.com/void-linux/void-packages/pull/30616

Description:
Looks like the upstream restructuring introduced a bug. Awaiting either upstream acknowledgment or downstream confirmation that this fix is sufficient.

Issue report: https://www.reddit.com/r/voidlinux/comments/n2nxyd/matplotlib_inline_broken_after_most_recent_update/
Proposed upstream fix: https://github.com/ipython/ipython/pull/12940