[Lazarus] Duplicate items in xml doc files

[Don Siders]

> makeskel does support update, the Makefile of fpc docs has even a target for
> it ?
> It only does additions, though.
> I suppose that deletions should also be easily added.
>
> Michael.

My initial efforts to use it were in the Lazarus 1.8.x time frame. and
it would not run without exception then. So I sought an alternate
mechanism.
I'd be glad to give it another try to see how it works out.

==
Don