Add no-content message for user/activity/replies, fix no-content display

app/assets/javascripts/discourse/routes/user-activity-replies.js.es6

@@ -2,5 +2,6 @@ import UserActivityStreamRoute from "discourse/routes/user-activity-stream";
 import UserAction from "discourse/models/user-action";
 
 export default UserActivityStreamRoute.extend({
-  userActionType: UserAction.TYPES["posts"]
+  userActionType: UserAction.TYPES["posts"],
+  noContentHelpKey: 'user_activity.no_replies'
 });

app/assets/javascripts/discourse/templates/user/stream.hbs

@@ -1,6 +1,4 @@
 {{#if model.noContent}}
-  <div class='no-content'>
-    {{{model.noContentHelp}}}
-  </div>
+  <div class='alert alert-info'>{{{model.noContentHelp}}}</div>
 {{/if}}
 {{user-stream stream=model}}

config/locales/server.en.yml

@@ -708,6 +708,9 @@ en:
     no_likes_given:
       self: "You have not liked any posts."
       others: "No liked posts."
+    no_replies:
+      self: "You have not replied to any posts."
+      others: "No replies."
 
   topic_flag_types:
     spam: