[RFA] Fix/complete option list/description in manual and in gdb --help.

[Eli Zaretskii]

> Date: Fri, 11 Jun 2021 21:26:42 +0200
> From: Philippe Waroquiers via Gdb-patches <gdb-patches@sourceware.org>
> 
> gdb/ChangeLog
> 2021-MM-DD  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
> 
> 	* main.c (captured_main_1): Have -w starting TUI to TK,
> 	use consistently -o or --option convention.
> 	(print_gdb_help): fix/complete help.
> 
> gdb/doc/ChangeLog
> 2021-MM-DD  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
> 
> 	* gdb.texinfo (Invoking GDB): Complete help.  Use -- systematically
>         for all long options.

Thank you for doing this.

> +Many options have both long and short forms.  Short options start with
> +@samp{-}, and long options start with @samp{--}.  @value{GDBN} also
> +recognizes the long forms if you truncate them, so long as enough of
> +the option is present to be unambiguous.  If an option requires a
> +value, the convention for long options is @samp{--option=value} and
> +@samp{-o value} for short options.
> +
> +Note however that @value{GDBN} accepts all of the following conventions
> +for most options:
> +
> +@table @code
> +@item --option=value
> +@item --option value
> +@item -option=value
> +@item -option value
> +@item -o value
> +@item -o=value
> +@item --o value
> +@item --o=value
> +@end table

The "value" parts above should have the @var markup.

> +@c NOTE: the @cindex entries here use double dashes ON PURPOSE.  This
> +@c way, both those who look for -foo and --foo in the index, will find
> +@c it.

Should this comment be before the text above, as it is relevant for it
as well?

The documentation part is OK with those nits taken care of.