mathlib

87f3aec4 - chore(topology/{fiber,vector}_bundle/*): reorganize files (#17559)

chore(topology/{fiber,vector}_bundle/*): reorganize files (#17559) The PR #17505 was a big refactor but left declarations in place. This PR proposes a reorganization to clean up: - new file `topology.fiber_bundle.is_homeomorphic_trivial_bundle` for the legacy `is_homeomorphic_trivial_fiber_bundle` construction (see [discussion](https://github.com/leanprover-community/mathlib/pull/17505#discussion_r1020865732)) - new file `topology.fiber_bundle.constructions` covering the trivial, fibrewise-product and pullback fiber bundles. The trivial-bundle material was previously split between `topology.{fiber,vector}_bundle.basic`, the prod material was previously in `topology.vector_bundle.prod`, the pullback material was previously in `topology.vector_bundle.pullback` - new file `topology.vector_bundle.constructions` covering the trivial, direct-sum and pullback vector bundles. The trivial-bundle material was previously in `topology.vector_bundle.basic`, the prod material was previously in `topology.vector_bundle.prod`, the pullback material was previously in `topology.vector_bundle.pullback` - delete files `topology.vector_bundle.prod` and `topology.vector_bundle.pullback`, whose material has all been moved elsewhere - delete construction `trivialization.comap`, which was morally (though not literally) a duplicate of `trivialization.pullback` - cleaner proof of `trivialization.prod.open_source`, removing a spurious dependence on an ambient fiber bundle structure - updated and augmented docs