Re: [PATCH v2] doc: clarify that --abbrev=<n> is about the minimum length

> Early text written in 2006 explains the "--abbrev=<n>" option to
> "show only a partial prefix", without saying that the length of the
> partial prefix is not necessarily the number given to the option to
> ensure that the output names the object uniquely.
> 
> Update documentation for the diff family of commands, "blame",
> "branch --verbose", "ls-files" and "ls-tree" to stress that the
> short prefix must uniquely refer to an object, and <n> is merely
> the mininum number of hexdigits used in the prefix.
> 
> Helped-by: Derrick Stolee <dstolee@microsoft.com>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
> 
>  * Thanks for your suggestion.  I decided to use "the shortest
>    prefix that is at least <n> hexdigits long".