Re: run pgindent on a regular basis / scripted manner

As a not very frequent submitter, on all the patches that I submit I
keep running into this problem. I have two open patchsets for
libpq[1][2] both of which currently include the same initial "run
pgindent" patch in addition to the actual patch, just so I can
actually run it on my own patch because a9e9a9f caused formatting to
totally be off in the libpq directory. And there's lots of other
changes that pgindent wants to make, which are visible on the job that
Magnus has set up.

To me a master branch that pgindent never complains about sounds
amazing! And I personally think rejection of unindented pushes and
cfbot complaining about unindented patches would be a very good thing,
because that seems to be the only solution that could achieve that.

Having cfbot complain also doesn't sound like a crazy burden for
submitters. Many open-source projects have CI complaining if code
formatting does not pass automatic formatting tools. As long as there
is good documentation on how to install and run pgindent I don't think
it should be a big problem. A link to those docs could even be
included in the failing CI job its error message. A pre-commit hook
that submitters/committers could install would be super useful too.
Since right now I sometimes forget to run pgindent, especially since
there's no editor integration (that I know of) for pgindent.

Side-question: What's the reason why pgindent is used instead of some
more "modern" code formatter that doesn't require keeping
typedefs.list up to date for good looking output? (e.g. uncrustify or
clang-format) Because that would also allow for easy editor
integration.

[1]: https://commitfest.postgresql.org/41/3511/
[2]: https://commitfest.postgresql.org/41/3679/