core-tutorial.txt: escape asterisk

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/Documentation/core-tutorial.txt b/Documentation/core-tutorial.txt
index 4211c81..d1360ec 100644
--- a/Documentation/core-tutorial.txt
+++ b/Documentation/core-tutorial.txt
@@ -971,7 +971,7 @@
 The first two lines indicate that it is showing the two branches
 and the first line of the commit log message from their
 top-of-the-tree commits, you are currently on `master` branch
-(notice the asterisk `*` character), and the first column for
+(notice the asterisk `\*` character), and the first column for
 the later output lines is used to show commits contained in the
 `master` branch, and the second column for the `mybranch`
 branch. Three commits are shown along with their log messages.