document that all on an empty set returns false

[panzi]

In every other language all() (or every()) returns true for an empty set (see e.g. every() in JavaScript: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every#description). This is because it is defined as (except with short circuiting):

let every = (array, func) => array.reduce((a, b) => a && func(b), true);

json-logic-js/logic.js

Lines 317 to 319 in c1dd82f

	if ( ! scopedData.length) {
	return false;
	}

I know that it can't be changed now, because that would break existing code. But I suspect there is code out there that assumes that all will return true on an empty set and is already broken. What I think needs to happen is that this is mentioned in the documentation as a big fat warning, so that people are aware of this unexpected behavior and write code accordingly.