GDB 11.1 release prep update (2021-08-24)

[Philippe Waroquiers]

On Tue, 2021-08-24 at 07:43 -0700, Joel Brobecker wrote:
> For Philippe's contribution (Fix/complete option list/description in
> manual and in gdb --help), it's on us Global Maintainers to review
> the patch; but on the other hand, I don't think this is critical either.
> Worse case, we can always backport to the .2 if felt important enough.

I will update the patch according to the comments received (i.e. use -this
as canonical form).
I do not think there is a need to backport this patch.

Thanks
Philippe