[PATCH] Add a notice to the doc of git-ls-tree.

["Steve Frécinaux" <code@istique.net>]

The notice covers this behaviour:
if you are in the git/ subdirectory of your repository, it will pick
the tree corresponding to that directory instead of the root one if you
specify the root tree object id.

Compare the output of both of those commands:
 git-ls-tree cb44e6571708aa2792c73a289d87586fe3c0c362
 git-cat-file -p cb44e6571708aa2792c73a289d87586fe3c0c362
---
 Documentation/git-ls-tree.txt |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/Documentation/git-ls-tree.txt b/Documentation/git-ls-tree.txt
index 1cdec22..7cba394 100644
--- a/Documentation/git-ls-tree.txt
+++ b/Documentation/git-ls-tree.txt
@@ -21,6 +21,10 @@ though - 'paths' denote just a list of patterns to match, e.g. so specifying
 directory name (without '-r') will behave differently, and order of the
 arguments does not matter.
 
+Note that if you give ls-tree the sha1 id of a parent of the tree
+corresponding to the directory you're in, it will resolve that tree and list
+its contents instead of listing the contents of the tree you gave.
+
 OPTIONS
 -------
 <tree-ish>::
-- 
1.5.6.2