Truncate merge request titles with periods instead of ellipsis

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/54862

app/models/commit.rb

@@ -177,7 +177,9 @@ class Commit
   def title
     return full_title if full_title.length < 100
 
-    full_title.truncate(81, separator: ' ', omission: '…')
+    # Use three dots instead of the ellipsis Unicode character because
+    # some clients show the raw Unicode value in the merge commit.
+    full_title.truncate(81, separator: ' ', omission: '...')
   end
 
   # Returns the full commits title

changelogs/unreleased/sh-truncate-with-periods.yml

+---
+title: Truncate merge request titles with periods instead of ellipsis
+merge_request: 23558
+author:
+type: changed

spec/models/commit_spec.rb

@@ -204,7 +204,7 @@ describe Commit do
       message = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec sodales id felis id blandit. Vivamus egestas lacinia lacus, sed rutrum mauris.'
 
       allow(commit).to receive(:safe_message).and_return(message)
-      expect(commit.title).to eq('Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec sodales id felis…')
+      expect(commit.title).to eq('Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec sodales id...')
     end
 
     it "truncates a message with a newline before 80 characters at the newline" do