Change Multiselect input placeholder text to translateable "Add"

data/core.yaml

@@ -261,6 +261,7 @@ en:
     check:
       "yes": "Yes"
       "no": "No"
+    add: Add
     none: None
     node: Node
     way: Way

dist/locales/en.json

@@ -316,6 +316,7 @@
             "yes": "Yes",
             "no": "No"
         },
+        "add": "Add",
         "none": "None",
         "node": "Node",
         "way": "Way",

js/id/ui/preset/multiselect.js

@@ -106,11 +106,9 @@ iD.ui.preset.multiselect = function(field, context) {
     function updateStrings(tagsData) {
         comboboxData = objectDifference(strings, tagsData);
         combobox.data(comboboxData.map(comboValues));
-        input.attr('placeholder', field.placeholder() ||
-            ( 'Type here'));
+        input.attr('placeholder', (field.placeholder() || t('inspector.add')) + '…');
     }
 
-
     function update(data) {
         var chips = multiselectContainer.selectAll('.chips').data(data);