Further break up metric dropdowns

nearest.html

@@ -57,7 +57,9 @@
       addOption("--- Compare to whole ---");
       Object.entries(metrics).forEach(([value, metric]) => {
         if (value === "theta") {
-          addOption("--- Compare to mean ---");
+          addOption("--- Angle to mean ---");
+        } else if (value === "delta") {
+          addOption("--- Distance to mean ---");
         } else if (value === "inertia") {
           addOption("--- Statistics ---");
         }