What problem does this feature solve?

1. Example code add Composition api support Vuejs docs recommend Composition api, but most of example code are Options api, so please add Composition api code example stay with Options api code example together. I do believe it will be good for Composition api.

2. Improve the Composition api compatible with Options api Vuejs docs say the Composition api equal to Options api, But I found that the example code has much more different, like: mounted ==> onMounted, computed ==> onComputed / ...,

   Why not let them use the same name in Composition api and Options api? Why not import them(ref/mounted/computed/created) automatically? I do think using the same name will be accepted quickly by most of users.