[RFA] Add "inf" alias for "info"

[Pierre Muller]

> I'm sure that you'll now get used to "i" in no time, now
> that you know it.

  Not that sure...
But I still think that the patch will be useful to others..
 
> This revealed an interesting issue.  The
> 
>  'Ambiguous command "inf reg": inferior, info.'
> 
> ... message doesn't indicate the aliases of each alternative
> command.  Neither does "help info" mention "i".  Maybe it should.
> 
> (btw, "i" + "inf" would leave "in" in a weird spot)
  But "in " was ambiguous before you added
"inferior", that is why I did not add it to the patch.
  Nobody using a recent gdb could have used
"in " like she/he could have used "inf ".

Pierre