bug#50110: [External] : Re: bug#50110: 26.3; Doc of `assoc': TESTFN optional arg

[Eli Zaretskii]

> From: Drew Adams <drew.adams@oracle.com>
> CC: "50110@debbugs.gnu.org" <50110@debbugs.gnu.org>
> Date: Wed, 18 Aug 2021 18:41:00 +0000
> 
> > > Neither the `assoc' doc string nor the Elisp manual, node `Association
> > > Lists' explains the order of the args that get passed to TESTFN.
> > 
> > It's a function that tests 2 objects for equality, so why does the
> > order matter?
> > 
> > > It's just as reasonable to expect that the pattern is the first arg to
> > > TESTFN, instead of, as is actually the case, the second arg.
> > 
> > There's no "pattern" in the doc string, so I don't think I understand
> > what you are describing here.
> 
> I gave examples.  What part is unclear?  To know how to use
> `string-match-p' for testing you need to know the arg order
> for TESTFN.  The arg order matters for `string-match-p'.

OK, I added description of how TESTFN is called.