man: use MIT-0 license for example codes in daemon(7)

This page contains many short example codes. I do not think we should
add SPDX-License-Identifier for all codes.

Closes #35356.

(cherry picked from commit 6046cc3)
(cherry picked from commit 6f2483e)
(cherry picked from commit cb1077c)
(cherry picked from commit 238f1f1)

Author: yuwata

man/daemon.xml

@@ -715,6 +715,15 @@ fi</programlisting>
     <citerefentry><refentrytitle>file-hierarchy</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
   </refsect1>
 
+  <refsect1>
+    <title>Notes</title>
+
+    <para>
+       All example codes in this page are licensed under <literal>MIT No Attribution</literal>
+      (SPDX-License-Identifier: MIT-0).
+    </para>
+  </refsect1>
+
   <refsect1>
     <title>See Also</title>
     <para>