constructor(tokens, comments, indexMap, startLoc, endLoc) {
		super();
		this.tokens = tokens;
		this.comments = comments;
		this.tokenIndex = utils.getLastIndex(tokens, indexMap, endLoc);
		this.commentIndex = utils.search(comments, endLoc) - 1;
		this.border = startLoc;
	}
Initializes this cursor.
@param {Token[]} tokens The array of tokens.
@param {Comment[]} comments The array of comments.
@param {Object} indexMap The map from locations to indices in `tokens`.
@param {number} startLoc The start location of the iteration range.
@param {number} endLoc The end location of the iteration range.