Feature: patch return new dom element

[hyrious]

Is your feature request related to a problem? Please describe.

If we patch a vnode to some element with different tag name,
the original element will be removed and be replaced with a new element.
The new element can not be accessed unless we do a `querySelector`.

Describe the solution you'd like

Let `patch()` returns the new element, so that we can keep a reference
to the real dom.

Describe alternatives you've considered

None.

Additional context

No response

[aidenybai]

Prototype implementation in #120, feel free to check it out. I'll merge it later if there are no issues. Thanks for the feature request