[PATCH] git-rev-parse.txt: Document ":path" specifier

[Michael J Gruber <git@drmicha.warpmail.net>]

The empty treeish in ":path" means "index", not "HEAD" like in probably
every other place.

Don't even try to change this, but at least document it.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
---
 Documentation/git-rev-parse.txt |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 8db600f..f964de4 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -290,8 +290,9 @@ the `$GIT_DIR/refs` directory or from the `$GIT_DIR/packed-refs` file.
   followed by something else than '!' is reserved for now.
 
 * A suffix ':' followed by a path; this names the blob or tree
-  at the given path in the tree-ish object named by the part
-  before the colon.
+  at the given path in the tree-ish object named by the ref
+  before the colon. An empty ref before ':' denotes the content
+  recorded in the index at the given path.
 
 * A colon, optionally followed by a stage number (0 to 3) and a
   colon, followed by a path; this names a blob object in the
-- 
1.7.1.621.g01d76