feat: compatible with @vitejs/plugin-vue2-jsx

[windsonR]

Description

When use @vitejs/plugin-vue2-jsx to transform jsx code, this plugin will not generate tag code in jsx file.

For example:

export default {
  render(){
    return (
       <some-tag/>
    )
  }
}

@vitejs/plugin-vue2-jsx will generate this code into

export default {
render(){
return h("some-tag")
}
}

unplugin's resolveVue2 function's RegExp
will not generate h function which generated by @vitejs/plugin-vue2-jsx.

This PR change the resolveVue2's RegExp to make sure unplugin will read the h function.

Linked Issues

Additional context

This RegExp looks have a problem.
It will match c not _c. and i don't know how to make the new RegExp match _c.but in my project, i test it(_c or c) has no difference.

[antfu]

We could use group to capture it.

[windsonR]

I have change it to group.
And I add a test for it.
please review it when you have time.
thanks