Make git cl smarter about subcommands typos.

Make git cl smarter about subcommands typos.

Look for either a unique prefix or for an approximation of the shortest
Levenshtein distance. So all of these will resolve to 'git cl upload':
  git cl upl
  git cl uplaod

These won't resolve:
  git cl up     # it shares prefix with 'upstream'
  git cl uplao  # not similar enough

Also align help against longest command instead of hard coded '10'. The help
page was distorded.

R=iannucci@chromium.org
BUG=

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=206820

[M-A Ruel, 2013-06-17 13:15:57]

I wanted to do this for a while. Today was the day.

[iannucci, 2013-06-17 19:41:25]

On 2013/06/17 13:15:57, Marc-Antoine Ruel wrote:
> I wanted to do this for a while. Today was the day.

What about confirming the command when doing a fuzzy match (as opposed to simply
a prefix lookup)?

  You typed 'uplaod', maybe you want to run 'upload' [Y/n]?

[M-A Ruel, 2013-06-17 19:43:48]

On 2013/06/17 19:41:25, iannucci wrote:
> On 2013/06/17 13:15:57, Marc-Antoine Ruel wrote:
> > I wanted to do this for a while. Today was the day.
> 
> What about confirming the command when doing a fuzzy match (as opposed to
simply
> a prefix lookup)?
> 
>   You typed 'uplaod', maybe you want to run 'upload' [Y/n]?

0.8 is very similar. I find it much more useful in practice than a confirmation
prompt. It gets the job done. The trade off is running a command you didn't
intend to, and that's why it looks first to make sure the top 2 most similar
commands are not too ambiguous.

[M-A Ruel, 2013-06-17 22:01:16]

On 2013/06/17 19:43:48, Marc-Antoine Ruel wrote:
> On 2013/06/17 19:41:25, iannucci wrote:
> > On 2013/06/17 13:15:57, Marc-Antoine Ruel wrote:
> > > I wanted to do this for a while. Today was the day.
> > 
> > What about confirming the command when doing a fuzzy match (as opposed to
> simply
> > a prefix lookup)?
> > 
> >   You typed 'uplaod', maybe you want to run 'upload' [Y/n]?
> 
> 0.8 is very similar. I find it much more useful in practice than a
confirmation
> prompt. It gets the job done. The trade off is running a command you didn't
> intend to, and that's why it looks first to make sure the top 2 most similar
> commands are not too ambiguous.

I decided to increase the minimum difference between the 2 best entries found to
make sure there's no ambiguity.

[iannucci, 2013-06-17 22:47:44]

lgtm

[commit-bot: I haz the power, 2013-06-17 22:50:44]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/maruel@chromium.org/17272002/7001

[commit-bot: I haz the power, 2013-06-17 22:52:25]

Change committed as 206820