Issue title: Bra-Ket notation not rendering
 Issue body: When trying to render Bra-Ket notation using the code given on https://katex.org/docs/supported.html#special-notation,  it is not rendering. 
 Comments: 
 Comment 0: This is due to react-latex being stuck on an outdated version of Katex (version 0.10.2) which does not include the Bra-Ket commands. I'd recommend implementing the functionality of react-latex yourself, so that you can have control of the version of Katex you're using. 
{'source': 'GithubIssues', 'repo_name_with_owner': 'zzish/react-latex', 'issue_id': 913461978, 'repo_stars': 152.0}