Fix lazy state

[josephjclark]

The lazy state operator $ is causing trouble if you try to use $ as a variable, a la:

parseXML(state.data, $ => {
    const inner = $.load(response.text()); // error
 });

This PR adds a bit of intelligence to the is-this-a-lazy-state-reference heuristic to ignore $ variable declared in the source. See the unit tests for details.

[josephjclark]

@mtuchi assuming this passes CI tests and it works for you, you can merge it and it'll be released! You'll have to ask Taylor to bump the lightning worker

[mtuchi]

@josephjclark let's hold this, i would love to test before merging.

[mtuchi]

Hiya @josephjclark i have tested this, it works as expected. Thanks for the fix 👍🏽

[mtuchi]

Tested locally on water-aid project, it works as expected 👍🏽