[RFA/doco] expand a bit the in-GDB help for the "catch exception" help text

  Hello,

One of our users remarked that the help doesn't mention the fact that
the "catch exception" supports the special argument "unhandled" to catch
exceptions which do not have a handler. This patch changes the output
of...

 | (gdb) help catch exception
 | Catch Ada exceptions, when raised.
 | With an argument, catch only exceptions with the given name.

... to ...

 | (gdb) help catch exception
 | Catch Ada exceptions, when raised.
 | Usage: catch exception [ ARG ]
 |
 | Without any argument, stop when any Ada exception is raised.
 | If ARG is "unhandled" (without the quotes), stop when an unhandledis raised.
 | Otherwise, the catchpoint only stops when the name of the exception being
 | raised is the same as ARG.

gdb/ChangeLog:

        * ada-lang.c (_initialize_ada_language): Expand the help text
        for the "catch exception" command.

Tested on x86_64-linux, no regression.

OK to push? Or any suggestions?

Thank you,
  

> From: Joel Brobecker <brobecker@adacore.com>
> Cc: Eli Zaretskii <eliz@gnu.org>
> Date: Fri, 11 Jan 2019 09:22:51 -0500
> 
>  | (gdb) help catch exception
>  | Catch Ada exceptions, when raised.
>  | Usage: catch exception [ ARG ]
>  |
>  | Without any argument, stop when any Ada exception is raised.
>  | If ARG is "unhandled" (without the quotes), stop when an unhandledis raised.
>  | Otherwise, the catchpoint only stops when the name of the exception being
>  | raised is the same as ARG.
> 
> gdb/ChangeLog:
> 
>         * ada-lang.c (_initialize_ada_language): Expand the help text
>         for the "catch exception" command.
> 
> Tested on x86_64-linux, no regression.
> 
> OK to push? Or any suggestions?

The text you propose LGTM, thanks (the text above includes a typo, but
the source patch gets it right).
  

> > gdb/ChangeLog:
> > 
> >         * ada-lang.c (_initialize_ada_language): Expand the help text
> >         for the "catch exception" command.
> > 
> > Tested on x86_64-linux, no regression.
> > 
> > OK to push? Or any suggestions?
> 
> The text you propose LGTM, thanks (the text above includes a typo, but
> the source patch gets it right).

Indeed; I accidently copy/pasted an old version of the text into
the commit log! The version I pushed has the correct text.

Thank you Eli!