mathlib3

0509c9c6 - fix(analysis/special_functions/pow): fix norm_num extension (#14099)

fix(analysis/special_functions/pow): fix norm_num extension (#14099) As [reported on Zulip](https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/kernel.20slow.20to.20accept.20refl.20proof/near/282043840).