Update for Bevy 0.15

[CosterM]

Support bevy 0.15
I have not changed any Bundles over to using required components, as it is not strictly necessary for 0.15 support

This depends on Leafwing-Studios/leafwing-input-manager#644

Notes:

• Doctests and examples were broken on main, so I fixed those so I could verify my changes. Let me know if you'd like a separate PR for those changes.
• examples/cooldown.rs is using crlf line endings for some reason? presumably not intended? I've left the line endings as is for this PR, so it doesn't look like i've changed the whole file when reviewing etc.
• The examples are affected by this issue Runtime error when using bevy_winit feature without explicitly adding bevy_window bevyengine/bevy#16568, so I have added an extra entry to the bevy features in dev-dependencies with a comment

[alice-i-cecile]

This looks great; thanks for all the fixes. I'll take a look at the linked LWIM PR too :)

examples/cooldown.rs is using crlf line endings for some reason? presumably not intended? I've left the line endings as is for this PR, so it doesn't look like i've changed the whole file when reviewing etc.

Yeah, this is unintended.