SLE 16 upgrade: Fix typo in assembly

Author: cwickert

articles/sle16-upgrade.asm.xml

@@ -172,7 +172,7 @@
                 <listitem>
                   <para>
                     A system with &productname; 15&nbsp;SP7. Upgrades from other &productnameshort;
-                    versions are not supported for @&productnameshort; 16.0.
+                    versions are not supported for &productnameshort; 16.0.
                   </para>
                 </listitem>
                 <listitem>