FIX: allow user quotes in HTML digest emails

spec/helpers/user_notifications_helper_spec.rb

@@ -34,5 +34,23 @@ describe UserNotificationsHelper do
       SiteSetting.digest_min_excerpt_length = 50
       expect(helper.email_excerpt(arg)).to eq([with_link, paragraphs[0]].join)
     end
+
+    it "uses user quotes but not post quotes" do
+      cooked = <<~HTML
+        <p>BEFORE</p>
+        <blockquote>
+          <p>This is a user quote</p>
+        </blockquote>
+        <aside class="quote" data-post="3" data-topic="87369">
+          <div class="title">A Title</div>
+          <blockquote>
+            <p>This is a post quote</p>
+          </blockquote>
+        </aside>
+        <p>AFTER</p>
+      HTML
+
+      expect(helper.email_excerpt(cooked)).to eq "<p>BEFORE</p><blockquote>\n  <p>This is a user quote</p>\n</blockquote><p>AFTER</p>"
+    end
   end
 end