The `bevy_ecs::schedule::schedule` module shares its name with its parent module

While working on https://github.com/bevyengine/bevy/pull/17335, I came across `bevy_ecs::schedule::schedule`, which was linting [`clippy::module_inception`](https://rust-lang.github.io/rust-clippy/master/index.html#module_inception).

I believe one module or the other should be renamed, as the current naming is confusing.

Start by locating bevy_ecs::schedule::schedule and its parent module, then trace references to both names. Review the module-inception lint context and confirm the rename removes the warning while all references continue to resolve.

Written by the indexing model from the issue text.