Mark Highligher.codeToHtml as non-nullable #101
Description
Highlither.codeToHtml is marked as a nullable property, however, as far as I can tell in practice, it will never be null.
https://github.com/shikijs/shiki/blob/master/packages/shiki/src/highlighter.ts#L91
Am I missing something, or can this be marked as non-nullable?