ls-tree documentation: enhance notes on subdirectory and pathspec behaviour
ls-tree documentation: enhance notes on subdirectory and pathspec behaviour

When run in a working copy subdirectory, git-ls-tree will automagically
add the prefix to the pathspec, which can result in an unexpected behavior
when the tree object accessed is not the root tree object.

Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git