Toponaming: Fix transformed; abstract index element name generation

src/App/ElementNamingUtils.cpp

@@ -91,4 +91,16 @@ bool Data::hasMissingElement(const char *subname) {
 
 const char *Data::hasMappedElementName(const char *subname) {
     return isMappedElement(findElementName(subname));
-}
+}
+
+// Currently used by CrossSection.cpp and FeatureTransformed.cpp with different label types
+// with a default of "I"  and "_" used by CrossSection.
+const std::string Data::indexSuffix(int index, const char *label)
+{
+    if ( index < 2 ) {  // Don't add a suffix for item #1, begin appending at 2
+        return {""};
+    }
+    std::string name(label);
+    name += std::to_string(index);
+    return name;
+}