Don't use diff_line_content for emails

app/helpers/diff_helper.rb

@@ -51,11 +51,9 @@ module DiffHelper
     html.html_safe
   end
 
-  def diff_line_content(line, email: false)
+  def diff_line_content(line)
     if line.blank?
       " ".html_safe
-    elsif email
-      line.html_safe
     else
       line.sub(/^[\-+ ]/, '').html_safe
     end

app/views/projects/diffs/_line.html.haml

@@ -25,7 +25,7 @@
         %a{href: "##{line_code}", data: { linenumber: link_text }}
     %td.line_content.noteable_line{ class: type, data: (diff_view_line_data(line_code, diff_file.position(line), type) unless plain) }<
       - if email
-        %pre= diff_line_content(line.text, email: true)
+        %pre= line.text
       - else
         = diff_line_content(line.text)