Use HAML class syntax in diff line partials

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

@@ -27,4 +27,4 @@
         = link_text
       - else
         = link_to "", "##{line_code}", id: line_code, data: { linenumber: link_text }
-    %td.line_content{ class: ['noteable_line', type, line_code], data: { line_code: line_code, position: position.to_json } }= diff_line_content(line.text, type)
+    %td.line_content.noteable_line{ class: [type, line_code], data: { line_code: line_code, position: position.to_json } }= diff_line_content(line.text, type)

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

@@ -14,11 +14,11 @@
           %td.new_line.diff-line-num
           %td.line_content.parallel.match= left[:text]
         - else
-          %td.old_line.diff-line-num{id: left[:line_code], class: "#{left[:type]} #{'empty-cell' if !left[:number]}"}
+          %td.old_line.diff-line-num{id: left[:line_code], class: [left[:type], ('empty-cell' unless left[:number])]}
             = link_to raw(left[:number]), "##{left[:line_code]}", id: left[:line_code]
             - if !@diff_notes_disabled && can?(current_user, :create_note, @project)
               = link_to_new_diff_note(left[:line_code], left[:position], 'old')
-          %td.line_content{class: "parallel noteable_line #{left[:type]} #{left[:line_code]} #{'empty-cell' if left[:text].empty?}", data: { line_code: left[:line_code], position: left[:position].to_json }}= diff_line_content(left[:text])
+          %td.line_content.parallel.noteable_line{class: [left[:type], left[:line_code], ('empty-cell' if left[:text].empty?)], data: { line_code: left[:line_code], position: left[:position].to_json }}= diff_line_content(left[:text])
 
           - if right[:type] == 'new'
             - new_line_class = 'new'
@@ -29,11 +29,11 @@
             - new_line_code = left[:line_code]
             - new_position = left[:position]
 
-          %td.new_line.diff-line-num{id: new_line_code, class: "#{new_line_class} #{'empty-cell' if !right[:number]}", data: { linenumber: right[:number] }}
+          %td.new_line.diff-line-num{id: new_line_code, class: [new_line_class, ('empty-cell' unless right[:number])], data: { linenumber: right[:number] }}
             = link_to raw(right[:number]), "##{new_line_code}", id: new_line_code
             - if !@diff_notes_disabled && can?(current_user, :create_note, @project)
               = link_to_new_diff_note(new_line_code, new_position, 'new')
-          %td.line_content.parallel{class: "noteable_line #{new_line_class} #{new_line_code} #{'empty-cell' if right[:text].empty?}", data: { line_code: new_line_code, position: new_position.to_json }}= diff_line_content(right[:text])
+          %td.line_content.parallel.noteable_line{class: [new_line_class, new_line_code, ('empty-cell' if right[:text].empty?)], data: { line_code: new_line_code, position: new_position.to_json }}= diff_line_content(right[:text])
 
       - unless @diff_notes_disabled
         - notes_left, notes_right = organize_comments(left, right)