mathlib

f6bab678 - feat(category_theory/limits/shapes/*): More API around kernel pairs. (#17301)

feat(category_theory/limits/shapes/*): More API around kernel pairs. (#17301) `is_kernel_pair` is also redefined to be a `Prop` using the new `is_pullback` api. Co-authored-by: Andrew Yang <36414270+erdOne@users.noreply.github.com>