patches.html: tfix

Reported-by: Melker Narikka <meklu@meklu.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
diff --git a/patches.html b/patches.html
index ae43963..2fdfe7a 100644
--- a/patches.html
+++ b/patches.html
@@ -102,7 +102,7 @@
     Such a tag is added near the end of the commit message, and has the form:
     </br>
     </br>
-    <span class="const">Signed-off-my: Firstname Lastname &lt;your-email-address&gt;</span>
+    <span class="const">Signed-off-by: Firstname Lastname &lt;your-email-address&gt;</span>
     </br>
     </br>
     For details, see the section on the "Developer's Certificate of Origin" in the file