submodule.c: use GIT_DIR_ENVIRONMENT consistently

diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index bf3bb372ee51397b362266d275cd557781585861..d8415734753e0d03f3f6d37bd4b76369d37f5fb0 100644 (file)
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -259,7 +259,9 @@ OPTIONS
 --branch::
        Branch of repository to add as submodule.
        The name of the branch is recorded as `submodule.<name>.branch` in
-       `.gitmodules` for `update --remote`.
+       `.gitmodules` for `update --remote`.  A special value of `.` is used to
+       indicate that the name of the branch in the submodule should be the
+       same name as the current branch in the current repository.
 
 -f::
 --force::