key option prefixes incorrectly

[stevenvachon]

const div = document.createElement('div');
div.innerHTML = `text1 text2`;
Splitting({ by: 'words', key: 'yeah', target: div });
console.log(div.outerHTML);

produces:

<div class=\"words splitting\" style=\"---yeahword-total: 2;\"><span class=\"word\" data-word=\"text1\" style=\"---yeahword-index: 0;\">text1</span><span class=\"whitespace\"> </span><span class=\"word\" data-word=\"text2\" style=\"---yeahword-index: 1;\">text2</span></div>

when it should instead produce:

<div class=\"words splitting\" style=\"--yeah-word-total: 2;\"><span class=\"word\" data-word=\"text1\" style=\"--yeah-word-index: 0;\">text1</span><span class=\"whitespace\"> </span><span class=\"word\" data-word=\"text2\" style=\"--yeah-word-index: 1;\">text2</span></div>

It happens with by: 'chars' too.

[stevenvachon]

Pretty sure it's caused by this: https://github.com/shshaw/Splitting/blob/1.1.0/src/core/splitting.js#L34

[stevenvachon]

@shshaw if I fix this, will you look at the PR?

[shshaw]

If you fix and add proper tests for it, I'm happy to take a look 👍