I agree that that is confusing and I would actually like to clean up that part of the API. Rather than having `setLineCommentSyntax(<array>)`, `addLineCommentSyntax(<string>)` would be better, I think - otherwise extensions cannot simply extend the set of line comments, but always replace them all. The JSON key should then be called lineComments (note the plural s) or even lineCommentPrefixes, and blockComment should be blockComments to allow multiple entries there, too.

What do you think?