clarify git's object garbage collection criteria a bit
diff --git a/got/git-repository.5 b/got/git-repository.5
index 7ada9c1..33eea33 100644
--- a/got/git-repository.5
+++ b/got/git-repository.5
@@ -136,8 +136,8 @@ directory, or in the
.Pa packed-refs
file which contains one reference definition per line.
.Pp
-Any object which is not reachable via a reference is subject to deletion
-by Git's garbage collector.
+Any object which is not directly or indirectly reachable via a reference
+is subject to deletion by Git's garbage collector.
.Sh FILES
.Bl -tag -width packed-refs -compact
.It Pa HEAD