Consider using doc examples when apropriate

## What problem does this solve or what need does it fill?

Bevy provides a ton of examples, which is great. But do all of them really need to be runnable?
For example, running [dynamic_types](https://github.com/bevyengine/bevy/blob/main/examples/reflection/dynamic_types.rs) is not very useful.

## What solution would you like?

I think examples like `dynamic_types` would fit better as doc examples. This would improve the user experience by having this information directly in the documentation. Additionally, binary examples take quite some time to compile.