patchsubmodule update: document exisiting -r form for --rebase

> From: "W. Trevor King" <wking@tremily.us>
>
> Signed-off-by: W. Trevor King <wking@tremily.us>
> ---
>  Documentation/git-submodule.txt | 3 ++-
>  git-submodule.sh                | 2 +-
>  2 files changed, 3 insertions(+), 2 deletions(-)

> diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
> index b4683bb..ec78fa7 100644
> --- a/Documentation/git-submodule.txt
> +++ b/Documentation/git-submodule.txt
> @@ -13,7 +13,7 @@ SYNOPSIS
>  	      [--reference <repository>] [--] <repository> [<path>]
>  'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...]
>  'git submodule' [--quiet] init [--] [<path>...]
> -'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--rebase]
> +'git submodule' [--quiet] update [--init] [-N|--no-fetch] [-r|--rebase]
>  	      [--reference <repository>] [--merge] [--recursive] [--] [<path>...]
>  'git submodule' [--quiet] summary [--cached|--files] [(-n|--summary-limit) <n>]
>  	      [commit] [--] [<path>...]
> @@ -251,6 +251,7 @@ OPTIONS
>  	If the key `submodule.$name.update` is set to `merge`, this option is
>  	implicit.
>  
> +-r::
>  --rebase::
>  	This option is only valid for the update command.
>  	Rebase the current branch onto the commit recorded in the
> diff --git a/git-submodule.sh b/git-submodule.sh
> index ab6b110..f2e8026 100755
> --- a/git-submodule.sh
> +++ b/git-submodule.sh
> @@ -8,7 +8,7 @@ dashless=$(basename "$0" | sed -e 's/-/ /')
>  USAGE="[--quiet] add [-b branch] [-f|--force] [--reference <repository>] [--] <repository> [<path>]
>     or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
>     or: $dashless [--quiet] init [--] [<path>...]
> -   or: $dashless [--quiet] update [--init] [-N|--no-fetch] [-f|--force] [--rebase] [--reference <repository>] [--merge] [--recursive] [--] [<path>...]
> +   or: $dashless [--quiet] update [--init] [-N|--no-fetch] [-f|--force] [-r|--rebase] [--reference <repository>] [--merge] [--recursive] [--] [<path>...]
>     or: $dashless [--quiet] summary [--cached|--files] [--summary-limit <n>] [commit] [--] [<path>...]
>     or: $dashless [--quiet] foreach [--recursive] <command>
>     or: $dashless [--quiet] sync [--] [<path>...]"

> "W. Trevor King" <wking@tremily.us> writes:
> 
> > From: "W. Trevor King" <wking@tremily.us>
> >
> > Signed-off-by: W. Trevor King <wking@tremily.us>
> > ---
> >  Documentation/git-submodule.txt | 3 ++-
> >  git-submodule.sh                | 2 +-
> >  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> Hmm, I wonder why I have this funny feeling that this was proposed
> and rejected already...
> 
> As the command takes other options whose names begin with 'r', I
> thought the longer term plan was to stop letting "--rebase" squat on
> short and sweet "-r" and leaving it undocumented (even though the
> short one was added by mistake) was meant to be the first step in
> that process.
> 
> But maybe I am confusing an undocumented single-letter option from
> some other subcommand.  Anybody remembers?

> Ah, this reminds me of another thing I noticed when I saw that
> patch.  The change seems to think "branch" is the _only_ thing the
> user might want to record per submodule upon "git submodule add".
> As an interface to muck with an uninterpreted random configuration,
> it squats on a good option name for setting one single and arbitrary
> variable---quite a selfish change that is not acceptable.
> 
> Calling the option "--record-branch-for-submodule" or something more
> specific might alleviate the problem, but then it would become even
> less useful as a short-hand for "config submodule.$name.branch", I
> would suspect.

>> As the command takes other options whose names begin with 'r', I
>> thought the longer term plan was to stop letting "--rebase" squat on
>> short and sweet "-r" and leaving it undocumented (even though the
>> short one was added by mistake) was meant to be the first step in
>> that process.
>> 
>> But maybe I am confusing an undocumented single-letter option from
>> some other subcommand.  Anybody remembers?
>
> Perhaps you are remembering:
>
> On Sun, Nov 11, 2012 at 02:33:45AM -0800, Junio C Hamano wrote:
>> Ah, this reminds me of another thing I noticed when I saw that
>> ...