Allow exclusion of this/self

[andrewcoughtrie]

It would be nice to be able to not show the this/self (sometimes called the "passed object dummy argument") argument in the generated documentation for type bound procedures. Also allowing it to not have a comment.

As you should never be passing this argument to a type bound procedure on use it is redundant and confusing to include it in the generated API docs.

[ZedThree]

I think this should be possible, but we'd need to look up the bound procedure to see if it has pass/nopass on it.