This PR is part of the issue #3492.
# Objective
- Add and update the bevy_dylib documentation to achieve a 100% documentation coverage.
- Add the #![warn(missing_docs)] lint to keep the documentation coverage for the future.
# Solution
- Add and update the bevy_dylib documentation.
- Add the #![warn(missing_docs)] lint.
# Objective
- CI jobs are starting to fail due to `clippy::bool-assert-comparison` and `clippy::single_component_path_imports` being triggered.
## Solution
- Fix all uses where `asset_eq!(<condition>, <bool>)` could be replace by `assert!`
- Move the `#[allow()]` for `single_component_path_imports` to `#![allow()]` at the start of the files.
