Re: [HACKERS] [PATCH] Remove trailing whitespaces from documentation

> They are considered bad practice in many style guides and many editors
> configured to stip them on every save.
>
> Such editors will produce spurious diffs when editing the documentation.
>
> Therefore, I propose this patch.

As mentioned down-thread, most of this is from psql output and I don't
know that we actually want to get rid of that whitespace.  Ideally, we
could indicate that trailing whitespace should be preserved when
printing examples, either with the SGML or the XML format.

The (relativly few) ones I include below do look like cases we should
probably fix and back-patch (to simplify later back-patching efforts).
Most of these only go back to 9.6 (parallel.sgml) anyway.