Update custom node documentation and the low-case example node to reduce Editor namespace clashes

Core Development Feature Requests
1

As seen in a recent Node-RED issue where the "bug" was actually in a custom node (now fixed). It is all too easy for node authors to break parts of Node-RED.

One small but useful way to help mitigate this is for Editor javascript to be wrapped in an IIFE:

(function () {
    'use strict'

    // .... "global" code here ....

    RED.nodes.registerType(moduleName, { /* .... */ });
}());

This immediately prevents leakage of "global" definitions from impacting Node-RED itself and does not seem to have any negative impacts (I've been using this in my own nodes for many years now).

I think it would be a useful tweak to use this pattern in documentation and in the lowercase example node.

2

If anyone wants to PR doc updates based on this request, that would always be welcome.

3

Done.