parseTree - Option to keep comments

Thanks for this library! I wrote a jsonc code formatter using it.

Right now I'm using the scanner to get the comments around the nodes in the tree. It would be slightly faster to not rescan these out and instead get all the comments when calling parseTree.

A simple solution would may be to have an option that returns all the comments in an array. Maybe something like...

export function parseTree(text: string, errors: ParseError[] = [], options: ParseOptions = ParseOptions.DEFAULT): Node;

Goes to:

export function parseTree(text: string, options: ParseOptions = ParseOptions.DEFAULT): ParseResult;

interface ParseResult {
	file: Node;
	errors: ParseError[];
	/** Included when `options.includeComments` is true. **/
	comments?: Comment[];
};

Then:

export interface ParseOptions {
	disallowComments?: boolean;
	allowTrailingComma?: boolean;
	allowEmptyContent?: boolean;
}

Goes to:

export interface ParseOptions {
	disallowComments?: boolean;
	includeComments?: boolean;
	allowTrailingComma?: boolean;
	allowEmptyContent?: boolean;
}

Thoughts? I could submit a PR for this, but will just need some direction on how the public API should look.