bug#35702: xref revert-buffer

[Eli Zaretskii]

> Cc: 35702@debbugs.gnu.org, juri@linkov.net
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Sat, 25 May 2019 18:47:57 +0300
> 
> Do you have any particular questions?

Thanks, but the purpose of my rant was not to follow up with
questions.  If I cannot convince you to clarify the code by adding
more comments, then I guess I failed, and let's drop this.