Explain different ways that props are treated in v3

In v3 v-on was merged with props, for that to happen props started with on* are treated as events

<Comp 
        @myEvent="log('myEvent')" 
        @my-event="log('my-event')"
        :onMyEvent="()=>log('onMyEvent')"
  />
  

<! -- CONVERTED TO  --> 
h(Comp, {
      onMyEvent: [
        _cache[0] || (_cache[0] = $event => (log('myEvent'))),
        _cache[1] || (_cache[1] = $event => (log('my-event'))),
        ()=>log('onMyEvent')
      ]
})

playground

You can also declare events as props

defineComponent({
  props: {
    onClick: Function, // similar to emit: ['click']
  }
})

Start with the v3 props and event examples in the issue and verify them in the linked playground. Update the relevant Vue documentation to explain how v-on handlers and on* props are treated, including declaring events as props; done means the examples and distinctions are clear to readers.