mathlib3

74c27b25 - feat(topology/sheaves): Pullback of presheaf (#9961)

feat(topology/sheaves): Pullback of presheaf (#9961) Defined the pullback of a presheaf along a continuous map, and proved that it is adjoint to pushforwards and it preserves stalks. Co-authored-by: erdOne <36414270+erdOne@users.noreply.github.com>