Add and apply Layout/DotPosition rule

Since IRB has improved its support for multiline, the main argument
towars using a trailing dot no longer affects most people.

It still affects me, though, since I use Pry :), but I agree
leading dots are more readable, so I'm enabling the rule anyway.

app/helpers/admin_budget_investments_helper.rb

@@ -22,8 +22,8 @@ module AdminBudgetInvestmentsHelper
   end
 
   def valuator_select_options(budget)
-    budget.valuators.order("description ASC").order("users.email ASC").includes(:user).
-      map { |v| [v.description_or_email, "valuator_#{v.id}"] }
+    budget.valuators.order("description ASC").order("users.email ASC").includes(:user)
+      .map { |v| [v.description_or_email, "valuator_#{v.id}"] }
   end
 
   def valuator_group_select_options