man: fix machine-id(5) man page reference

Spotted whilst debugging:
```
[763/2094] Generating man/machine-info.html with a custom command
Element cite in namespace '' encountered in para, but no template matches.
[765/2094] Generating man/machine-info.5 with a custom command
Element cite in namespace '' encountered in para, but no template matches.
```

Follow-up to 357376d0bb5.

diff --git a/man/machine-info.xml b/man/machine-info.xml
index b4b5af26e08a1ad79d9d0d393b3665ce80aaa186..d324856d07adb6e9bcff974a8fe9752ac7364fb7 100644 (file)
--- a/man/machine-info.xml
+++ b/man/machine-info.xml
@@ -136,7 +136,8 @@
         <command>kernel-install</command> should use. The value must be a valid machine ID (32 hexadecimal
         characters). This would generally be the original machine-id that was used when the boot loader
         entries for this installation were first added. When not set, the current value of
-        <cite>machine-id(5)</cite> will be used.</para></listitem>
+        <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+        will be used.</para></listitem>
       </varlistentry>
     </variablelist>
   </refsect1>