Add LIMIT to sql keywords

[bjacobso]

I think LIMIT should be an included keyword for SQL, considering OFFSET is already included in the list

[msftclas]

This seems like a small (but important) contribution, so no Contribution License Agreement is required at this point. We will now review your pull request.
Thanks,
Microsoft Pull Request Bot

[bjacobso]

Or a supported way to decorate default languages would also work? Here is my hacky workaround:

var _setMonarchTokensProvider = window.monaco.languages.setMonarchTokensProvider;
window.monaco.languages.setMonarchTokensProvider = (languageId, lang) => {
  lang.keywords.push('LIMIT', 'AND', 'OR');
  _setMonarchTokensProvider(languageId, lang)
};

[rebornix]

@bjacobso LGTM, thanks!