Updated html2xt to use unpacked dicts when attr keys are not valid python names

[matdmiller]

Updated html2xt to use unpacked dicts when attr keys are not valid python names.

Also added example of using an unpacked dict to the explaining components nb.

Minimal Example:

hl_md(html2xt_new('<div x-data="{open: false}" x-init="console.log(\'Initialized\')" @click="open = !open">Toggle</div>'))

to

Div('Toggle', x_data='{open: false}', x_init="console.log('Initialized')", **{'@click':'open = !open'})

[matdmiller]

@jph00 just mentioning you to put this on your list in gh when you get a chance to look at it.