Use faster, more appropriate pipeline for mentionable attributes

app/models/commit.rb

@@ -7,7 +7,7 @@ class Commit
   include Referable
   include StaticModel
-  attr_mentionable :safe_message
+  attr_mentionable :safe_message, pipeline: :single_line
   participant :author, :committer, :notes
   attr_accessor :project

app/models/concerns/issuable.rb

@@ -46,7 +46,7 @@ module Issuable
              allow_nil: true,
              prefix: true
-    attr_mentionable :title 
+    attr_mentionable :title, pipeline: :single_line
     attr_mentionable :description, cache: true
     participant :author, :assignee, :notes_with_associations
   end