Allowed linked form onsubmit trigger

[linkdotnet]

Currently, bUnit allows the following:

<form @onsubmit="...">
 <button type="submit">...

// This will trigger the onsubmit event
cut.Find("button").Click();

That follows the HTML spec very closely. But the following is not possible:

<form id="form1" @onsubmit="...">
</form>

<button form="form1" type="submit"></button>

This is a follow-up from #1765 reported by @Jorn96