bug#49926: [PATCH] Fix NNIMAP search command in the gnus

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Jan Stranik via "Bug reports for GNU Emacs, the Swiss army knife of text
editors" <bug-gnu-emacs@gnu.org> writes:

> In the version 27.2 of emacs, the nnimap search commands stopped
> working in gnus.
>
> Good example is a command AT to find a referred
> thread in the summary buffer. The observed behaviour was that the
> search command returned no error.
>
> The problem turned out to be in the way how imap query is sent to the
> server. The function nnimap-make-thread-query used a format function
> with foramt specifier %S. For string values with formatting the string
> returned is in the format #("string" ....). The result was tha the
> query sent to the server looked like:
>   23:52:00 [stranik.org] 1980 UID SEARCH (OR HEADER REFERENCES #("<87pmurac3u.fsf@stranik.org>" 0 28 (ws-butler-chg chg)) HEADER Message-Id #("<87pmurac3u.fsf@stranik.org>" 0 28 (ws-butler-chg chg)))
>
> which is an invalid query.
>
> The change formats the string with %s specifier which discards text
> properties.

But that also removes the quoting around the message ids -- are we sure
that's still valid?