[RFA] Show locno for 'multi location' breakpoint hit msg+conv var $bkptno $locno.

[Eli Zaretskii]

> Date: Fri, 3 Jun 2022 13:40:00 -0700
> From: Keith Seitz via Gdb-patches <gdb-patches@sourceware.org>
> 
> I looked up the history of this patch a bit to understand the motivation
> for querying co-workers... I see Eli commented in the original April
> discussion:
> 
> > I'm not sure everyone will want to see the likes of
> >
> >  Thread 1 "foobar" hit breakpoint 10.42, some_func () at ...
> >
> > But that's MO; I'd be interested in opinions of others.
> 
> Well, I'm not a global maintainer, but I'll chime in with my opinion,
> if everyone will permit me. [Ha! You're already reading it!]
> 
> I don't think it is a big deal to see ".42" in the output. Far more
> irritating is not knowing exactly which of the many locations it hit.
> I've always felt this was akin to ambiguous output by GDB. "You hit
> breakpoint X." Oh, wait, that's one of fifty different real breakpoints.

We show the source line where the breakpoint breaks right after this,
so at least some of the ambiguity is resolved by that.