Use both key and value for grid reference

js/id/ui/tag_reference.js

@@ -29,7 +29,7 @@ iD.ui.TagReference = function(entity, tag) {
     return function(selection) {
         selection.html('');
 
-        taginfo.docs({key: tag.key}, function(err, docs) {
+        taginfo.docs(tag, function(err, docs) {
             if (!err && docs) {
                 docs = findLocal(docs);
             }

js/id/ui/taglist.js

@@ -98,7 +98,7 @@ iD.ui.Taglist = function(context, entity) {
                 d3.select(d3.select(this).node().parentNode)
                     .select('div.tag-help')
                     .style('display', 'block')
-                    .call(iD.ui.TagReference(entity, tag));
+                    .call(iD.ui.TagReference(entity, {key: tag.key}));
             })
             .append('span')
             .attr('class', 'icon inspect');