Docs: @with_children UI component pattern

[bessey]

Add documentation for the pattern described in #6 (comment)

I've tried to make the example consistent with the patterns in the other examples (namely, importing each element individually rather than import htpy as h).

Wasn't sure if this should live in docs/ or examples/ or both.

[bessey]

Ah, actually this example doesn't work quite how I envisioned. It requires that you call the function, as opposed to e.g. htpy.div where you can either htpy.div()[] or htpy.div[].

I guess that's unavoidable while using a decorator, since we must return a function which must be called. Is that right @pelme?

[pelme]

I think you could implement __call__() on _ChildrenWrapper to support both patterns.

[bessey]

Makes sense. FYI right now I've moved on to dabbling with another side project so I don't expect to follow up with changes anytime soon

[pelme]

Closing this PR since there is no activity/desire to keep working on it. Feel free to use this work for starting a new!

[davepeck]

Makes sense. I never fell in love with any of the patterns I played with for this.