add type to usage

src/main/java/gov/usgs/earthquake/nshmp/www/gmm/ServiceUtil.java

@@ -387,12 +387,14 @@ class ServiceUtil {
 
       final String id;
       final String label;
+      final Gmm.Type type;
       final ArrayList<String> supportedImts;
       final Constraints constraints;
 
       Value(Gmm gmm) {
         this.id = gmm.name();
         this.label = gmm.toString();
+        this.type = gmm.type();
         this.supportedImts = supportedImts(gmm.supportedImts());
         this.constraints = gmm.constraints();
       }