Always use colon at end of discussion notification email headline

app/views/notify/_note_email.html.haml

@@ -4,17 +4,13 @@
 - note_style = local_assigns.fetch(:note_style, "")
 
 - discussion = note.discussion if note.part_of_discussion?
-- diff_discussion = discussion&.diff_discussion?
-- on_image = discussion.on_image? if diff_discussion
 
 - if discussion
-  - phrase_end_char = on_image ? "." : ":"
-
   %p{ style: "color: #777777;" }
-    = succeed phrase_end_char do
+    = succeed ':' do
       = link_to note.author_name, user_url(note.author)
 
-      - if diff_discussion
+      - if discussion&.diff_discussion?
         - if discussion.new_discussion?
           started a new discussion
         - else
@@ -31,7 +27,7 @@
   %p.details
     #{link_to note.author_name, user_url(note.author)} commented:
 
-- if diff_discussion && !on_image
+- if discussion&.diff_discussion? && discussion.on_text?
   = content_for :head do
     = stylesheet_link_tag 'mailers/highlighted_diff_email'
 

spec/mailers/notify_spec.rb

@@ -890,22 +890,14 @@ describe Notify do
       shared_examples 'an email for a note on a diff discussion' do  |model|
         let(:note) { create(model, author: note_author) }
 
-        context 'when note is on image' do
+        context 'when note is not on text' do
           before do
-            allow_any_instance_of(DiffDiscussion).to receive(:on_image?).and_return(true)
+            allow_any_instance_of(DiffDiscussion).to receive(:on_text?).and_return(false)
           end
 
           it 'does not include diffs with character-level highlighting' do
             is_expected.not_to have_body_text '<span class="p">}</span></span>'
           end
-
-          it 'ends the intro with a dot' do
-            is_expected.to have_body_text "#{note.diff_file.file_path}</a>."
-          end
-        end
-
-        it 'ends the intro with a colon' do
-          is_expected.to have_body_text "#{note.diff_file.file_path}</a>:"
         end
 
         it 'includes diffs with character-level highlighting' do