Link to required components docs in component type docs

[Jondolf]

Objective

#16575 moved required component docs from the Component impl to type docs.

However, it doesn't actually link to what required components are and how they work.

Solution

Link to required components!

Testing

I tested the link for some components in different Bevy crates. I did not test in external third party crates, but I would assume that it should work there too.

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Showcase

Note: The tooltip doesn't show the #required-components anchor for some reason, but it is there.

[SpecificProtagonist]

I did not test in external third party crates, but I would assume that it should work there too.

This works when using bevy_ecs directly, but not when depending on bevy:

A component’s [required components](bevy :: ecs::component::Component#required-components) are inserted whenever it is inserted. Note that this will also insert the required components of the required components, recursively, in depth-first order.