feat(data/nat/digits): digits injective at fixed base (#6338)
feat(data/nat/digits): digits injective at fixed base (#6338)





Co-authored-by: Yury G. Kudryashov <2c59405d0ec2e119a1c3d2318bdb4a6ce50051ae@urkud.name>

leanprover-community/mathlib,leanprover-community/mathlib