Use aria-label in admin table actions

This way screen reader users will know which record they're going to
access when focusing on a link to a certain action. Otherwise they'd
hear something like "Edit, link", and they wouldn't know which record
they'll end up editing if they follow the link.

app/models/poll/booth_assignment.rb

@@ -3,6 +3,8 @@ class Poll
     belongs_to :booth
     belongs_to :poll
 
+    delegate :name, to: :booth
+
     before_destroy :destroy_poll_shifts, only: :destroy
 
     has_many :officer_assignments, dependent: :destroy

app/models/poll/shift.rb

@@ -16,6 +16,10 @@ class Poll
     after_create :create_officer_assignments
     before_destroy :destroy_officer_assignments
 
+    def title
+      "#{I18n.t("admin.poll_shifts.#{task}")} #{officer_name} #{I18n.l(date.to_date, format: :long)}"
+    end
+
     def persist_data
       self.officer_name = officer.name
       self.officer_email = officer.email