CLDR-11155 Separate Volume_Metric and Volume_Other

-New subroutines makePathHeader and getVolumePageId

-Change example in Dashboard.java from Volume to Area

-Comments

tools/cldr-code/src/main/java/org/unicode/cldr/util/PathHeader.java

@@ -800,6 +800,10 @@ private PageId getVolumePageId(String path) {
             if (!Collections.disjoint(METRIC, unitSystemCollection)) {
                 return PageId.Volume_Metric;
             } else {
+                // TODO: some metric paths are included in Volume_Other instead of in Volume_Metric,
+                // such as
+                // //ldml/units/unitLength[@type="narrow"]/unit[@type="volume-cubic-kilometer"]/displayName
+                // Reference: https://unicode-org.atlassian.net/browse/CLDR-11155
                 return PageId.Volume_Other;
             }
         }