BUGFIX: add [PM] string to private message emails

app/mailers/user_notifications.rb

@@ -141,8 +141,9 @@ class UserNotifications < ActionMailer::Base
       locals: { context_posts: context_posts, post: @post }
     )
 
+    template = "user_notifications.user_#{notification_type}"
     if @post.topic.private_message?
-      opts[:subject_prefix] = "[#{I18n.t('private_message_abbrev')}] "
+      template << "_pm"
     end
 
     email_opts = {
@@ -155,10 +156,9 @@ class UserNotifications < ActionMailer::Base
       username: username,
       add_unsubscribe_link: true,
       allow_reply_by_email: opts[:allow_reply_by_email],
-      template: "user_notifications.user_#{notification_type}",
+      template: template,
       html_override: html,
-      style: :notification,
-      subject_prefix: opts[:subject_prefix] || ''
+      style: :notification
     }
 
     # If we have a display name, change the from address

config/locales/server.en.yml

@@ -1183,6 +1183,16 @@ en:
         ---
         %{respond_instructions}
 
+    user_posted_pm:
+      subject_template: "[%{site_name}] [PM] %{topic_title}"
+      text_body_template: |
+        %{message}
+
+        %{context}
+
+        ---
+        %{respond_instructions}
+
     digest:
       why: "Here's a brief summary of the discussion on %{site_link} since we last saw you on %{last_seen_at}."
       subject_template: "[%{site_name}] Forum Activity for %{date}"