[PATCH 2/2] Documentation/diff-options: reword description of --submodule option

[Tim Henigan <tim.henigan@gmail.com>]

The previous description was a bit confusing.  This rewrite makes it
easier to understand.

It should be noted that even though 'log' is listed as the default
format, it is not used when the '--submodule' option is missing. This
means that the output of:
   'git diff'             matches 'git diff --submodule=short'
   'git diff --submodule' matches 'git diff --submodule=log'

Signed-off-by: Tim Henigan <tim.henigan@gmail.com>
---

Resent due to a typo in the developer list email address.

I will understand if this change is rejected, but I found the current
description difficult to follow the first couple times I read it.

 Documentation/diff-options.txt |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index f44f3fc..0e1c753 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -165,11 +165,10 @@ any of those replacements occurred.
 	of the `--diff-filter` option on what the status letters mean.
 
 --submodule[=<format>]::
-	Choose the output format for submodule differences. <format> can be one of
-	'short' and 'log'. 'short' just shows pairs of commit names, this format
-	is used when this option is not given. 'log' is the default value for this
-	option and lists the commits in that commit range like the 'summary'
-	option of linkgit:git-submodule[1] does.
+	Choose the output format for submodule differences. <format> can be one
+	of 'short' or 'log'. The default value is 'log'.
+	'log' lists commits in the commit range like linkgit:git-submodule[1] `--summary`.
+	'short' shows only the SHA1 of the source and destination.
 
 --color[=<when>]::
 	Show colored diff.
-- 
1.7.10.rc0