types: about VNodeRef

[hcg1023]

I see the Element type used in the runtime-core package, and the runtime-core package used in vue as a cross-framework package. Is this correct?
我看到在runtime-core包中使用了Element类型，这个类型应该是dom独有的，runtime-core包应该是一个跨框架的形态，我不知道这样是否正确

The error was detected when using the ref function type in template.

Corresponding commit: 0c7fd13