bug#21800: Fix HEX ADDR values in hexl-mode doc string

[Eli Zaretskii]

> From: Mihai Olteanu <mihai_olteanu@fastmail.fm>
> Date: Sat, 31 Oct 2015 13:41:19 +0200
> 
> Please find bellow the ChangeLog and the Patch for fixing the
> hexadecimal address
> values that appear in the documentation string for hexl-mode. 
> Visiting a file in hexl mode displays the addresses in the 00, 11, 22,
> etc. format, not
> 00, 01, 02, etc. format that is currently given as an example in the
> above mentioned 
> doc string.

Thanks, I pushed this.