fix: rangeless multi chars highlighting

[atomiks]

Fixes #166

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[atomiks]

This one still fails: /get/ doesn't highlight all instances

/Length/1 /str/ /const/2-3 /get/

```js /Length/1 /str/ /const/2-3 /get/
const getStringLength = (str) => str.length;

const strLen = getStringLength('str');

const anotherStrLen = getStringLength('anotherStr');
```

[atomiks]

^Seems to be a separate issue regarding overlapping chars. It inherits the range from whichever node contains the textContent to be highlighted, even if the other chars aren't included. I will file a separate issue for that one.