Adds a new option to IParseOptions, alternateComment.

[gideongoodwin]

If this new flag is true, the tokenizer will change the way it parses comments from the input. Instead of requiring /// or /** / (docblock style) comments only, it will additionally accept // and / */ comments. It will consecutive lines of // comments into one multi-line comment.

The motivation here is that we want to parse comments in customer api descriptions which don't adhere to the docblock style.

[dcodeIO]

What do you think of doing something like

isDoc = (charAt(start = offset) === "/" && ++offset) || alternateCommentMode;

here so it always handles /// and advances properly, and otherwise falls back to // in alternateCommentMode? Just asking because it seems that duplicating this section could potentially be avoided.

I'd say it would be fine if /// in non-alternateCommentMode also coalesces consecutive lines.

[gideongoodwin]

Thanks for looking. I agree that avoiding duplication would be good, however I am hesitant to change existing behavior in case other consumers of this library depend on it.

In the spirit of your comment, I consolidated the /* handling for original and alternate parsing modes. The ////// handling is a bit too divergent to consolidate further.

[dcodeIO]

Looking good, thank you!