Add plural form support for multiselection page title (close #8026)

data/core.yaml

@@ -22,7 +22,9 @@ en:
       context: "{base} – {context}"
       changes: "({changes}) {base}"
       changes_context: "({changes}) {base} – {context}"
-    labeled_and_more: "{labeled} and {count} more"
+    labeled_and_more:
+      one: "{labeled} and {count} more"
+      other: "{labeled} and {count} more"
   modes:
     add_area:
       title: Area

dist/locales/en.json

@@ -26,7 +26,10 @@
                 "changes": "({changes}) {base}",
                 "changes_context": "({changes}) {base} – {context}"
             },
-            "labeled_and_more": "{labeled} and {count} more"
+            "labeled_and_more": {
+                "one": "{labeled} and {count} more",
+                "other": "{labeled} and {count} more"
+            }
         },
         "modes": {
             "add_area": {

modules/behavior/hash.js

@@ -62,7 +62,7 @@ export function behaviorHash(context) {
             if (selected.length > 1 ) {
                 contextual = t('title.labeled_and_more', {
                     labeled: firstLabel,
-                    count: (selected.length - 1).toString()
+                    count: selected.length - 1
                 });
             } else {
                 contextual = firstLabel;