Ignore text in JSX tags

[stilt0n]

People can type whatever they want between JSX tags, including valid / invalid ES imports. We need to be able to ignore these cases. E.g.:

return <p>the import keyword in jsx should be ignored</p>

Will panic because it does not expect a standalone slash.

Challenges:

// can't just count <div> and </div> tag instances to tell when JSX is over
// without being able to tell <div {...props}> matches </div>
<div onClick={ /* ... */} /><div>import</div></div>

// <foo ? x> is not a JSX tag and we shouldn't try to treat it as such:
5<foo ? x>8 : false;