clone: define shallow clone boundary with --shallow-exclude

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/git-clone.txt b/Documentation/git-clone.txt
index a410409..5049663 100644
--- a/Documentation/git-clone.txt
+++ b/Documentation/git-clone.txt
@@ -196,6 +196,11 @@
 --shallow-since=<date>::
 	Create a shallow clone with a history after the specified time.
 
+--shallow-exclude=<revision>::
+	Create a shallow clone with a history, excluding commits
+	reachable from a specified remote branch or tag.  This option
+	can be specified multiple times.
+
 --[no-]single-branch::
 	Clone only the history leading to the tip of a single branch,
 	either specified by the `--branch` option or the primary