replace `is_dashboard_milestone?` with `dashboard_milestone?`

app/models/concerns/milestoneish.rb

@@ -82,7 +82,7 @@ module Milestoneish
     false
   end
 
-  def is_dashboard_milestone?
+  def dashboard_milestone?
     false
   end
 

app/models/dashboard_milestone.rb

@@ -3,7 +3,7 @@ class DashboardMilestone < GlobalMilestone
     { authorized_only: true }
   end
 
-  def is_dashboard_milestone?
+  def dashboard_milestone?
     true
   end
 end

app/views/shared/milestones/_top.html.haml

@@ -44,7 +44,7 @@
     - close_msg = group ? 'You may close the milestone now.' : 'Navigate to the project to close the milestone.'
     %span All issues for this milestone are closed. #{close_msg}
 
-- if @milestone.legacy_group_milestone? || @milestone.is_dashboard_milestone?
+- if @milestone.legacy_group_milestone? || @milestone.dashboard_milestone?
   .table-holder
     %table.table
       %thead