Loosen up the death grip on #19 with `switch`

* `switch` is designed to handle multiple logic cases since ES3 and forward.
* There is no requirement for the prior restrictions in any of the styleguides currently mentioned in #19
* Noted that curly braces can be used for code folding, otherwise they are mostly useless imho and as far as I know
* Added `expressionNth` to the sample with a simple fall through.
* GMs requirement of adding a comment for fallthroughs seems rather tautological since this is how the statement has been in the C family of languages and all of its derivatives for many decades.

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Unless I'm missing something entirely the prior restriction was/is "ludicrous"... I am open to read any missed reasoning why this was initially drafted into the STYLEGUIDE.md and why we would want to prevent a set of logic paths from being used with a core statement.

See also:
* https://github.com/OpenUserJs/OpenUserJS.org/commit/0263c797d323cdf76be9cd6f11093903ea250b69#commitcomment-6905688 from ~2 days ago which went out to all admins with no response... so bringing it front and center here with a sooner label since there has been some time to think about this already.

> Doesn't this only apply to node?

Yes but the STYLEGUIDE.md is for our project here which uses node.js... some of my styling for my own user.js is different than the styling for this project. Ex. I don't cuddle if...else because of code folding... just a personal preference.