Allow `this` to be used in hx-trigger

Feature request:

I'd like the form is submitted on some events on its children. I can do this right now as:

```

One
Two

Three
Four

```

However, I do not like the idea that I have to introduce and use the form IDs just for mentioning elements inside the form (this is making the automatically generated content of such forms harder to read)
So, I'd prefer something simpler, for example: `change from:this input` -- where `this` is used for mentioning the element itself as in hx-target.
Another option that I think should be fine: `change from:findAll input`

Thanks.

P.S. The `change from:find input` does not work as it only assign event listener to single input (the first checkbox in the above example).
P.P.S. The `change from:closest (form input)` does not work as well and I do not understand why as based on ur manual `closest` should match itself.