UX: better wording when there are no unused tags to delete

UX: better wording when there are no unused tags to delete

diff --git a/app/assets/javascripts/discourse/app/controllers/tags-index.js b/app/assets/javascripts/discourse/app/controllers/tags-index.js
index 75806c5..3d689eb 100644
--- a/app/assets/javascripts/discourse/app/controllers/tags-index.js
+++ b/app/assets/javascripts/discourse/app/controllers/tags-index.js
@@ -64,6 +64,12 @@ export default Controller.extend({
         .then(result => {
           const displayN = 20;
           const tags = result["tags"];
+
+          if (tags.length === 0) {
+            bootbox.alert(I18n.t("tagging.delete_no_unused_tags"));
+            return;
+          }
+
           const joinedTags = tags.slice(0, displayN).join(", ");
           var more = Math.max(0, tags.length - displayN);
 
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index ad29da0..9cc2bc8 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -3355,6 +3355,7 @@ en:
       delete_unused_confirmation_more_tags:
         one: "%{tags} and %{count} more"
         other: "%{tags} and %{count} more"
+      delete_no_unused_tags: "There are no unused tags."
       delete_unused: "Delete Unused Tags"
       delete_unused_description: "Delete all tags which are not attached to any topics or personal messages"
       cancel_delete_unused: "Cancel"

GitHub sha: 96511e45