mathlib3

02f2f947 - refactor(category_theory/finite_limits): missing piece of #3320 (#3400)

refactor(category_theory/finite_limits): missing piece of #3320 (#3400) A recent PR #3320 did some refactoring of special shapes of limits. It seems I forgot to include `wide_pullbacks` in that refactor, so I've done that here. Co-authored-by: Scott Morrison <scott.morrison@gmail.com>