fix typo

conf/vanilla/sip_profiles/internal.xml

@@ -180,7 +180,7 @@
     <!--<param name="unregister-on-options-fail" value="true"/>-->
     <!-- Send an OPTIONS packet to all registered endpoints -->
     <!--<param name="all-reg-options-ping" value="true"/>-->
-    <!-- Send an OPTIONS packet to NATed registered endpoints. Can be 'true' or 'udp-only'. --!>
+    <!-- Send an OPTIONS packet to NATed registered endpoints. Can be 'true' or 'udp-only'. -->
     <!--<param name="nat-options-ping" value="true"/>-->
 
     <!-- TLS: disabled by default, set to "true" to enable -->