Add and appy MultilineOperationIndentation rule

This way it's easier to see when lines are part of multiline
statements and when they belong to `if` statements.

app/helpers/poll_recounts_helper.rb

@@ -2,8 +2,8 @@ module PollRecountsHelper
   def total_recounts_by_booth(booth_assignment)
     if booth_assignment.recounts.any?
       booth_assignment.recounts.sum(:total_amount) +
-      booth_assignment.recounts.sum(:white_amount) +
-      booth_assignment.recounts.sum(:null_amount)
+        booth_assignment.recounts.sum(:white_amount) +
+        booth_assignment.recounts.sum(:null_amount)
     end
   end
 end