Add frozen_string_literal magic comment

re: https://www.rubydoc.info/gems/rubocop/RuboCop/Cop/Style/FrozenStringLiteralComment

app/views/admin/booths/_all_booths.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb.add_worksheet(name: 'all booths') do |sheet|
   bold_style = wb.styles.add_style(b: true)
   wrap_text = wb.styles.add_style alignment: {wrap_text: true}

app/views/admin/booths/_confirmed_booths.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb.add_worksheet(name: 'all booths') do |sheet|
   bold_style = wb.styles.add_style(b: true)
   wrap_text = wb.styles.add_style alignment: {wrap_text: true}

app/views/admin/booths/booths.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb = xlsx_package.workbook
 xlsx_package.use_autowidth = true
 if @booth_export_option == 'confirmed'

app/views/admin/events/_all_events.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb.add_worksheet(name: 'all events') do |sheet|
   bold_style = wb.styles.add_style(b: true)
   wrap_text = wb.styles.add_style alignment: {wrap_text: true}

app/views/admin/events/_all_with_comments.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb.use_shared_strings = true
 wb.add_worksheet(name: 'events with comments') do |sheet|
   bold_style = wb.styles.add_style(b: true)

app/views/admin/events/_confirmed_events.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb.add_worksheet(name: 'confirmed events') do |sheet|
   bold_style = wb.styles.add_style(b: true)
   wrap_text = wb.styles.add_style alignment: {wrap_text: true}

app/views/admin/events/events.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb = xlsx_package.workbook
 if @event_export_option == 'confirmed'
   render partial: 'confirmed_events', locals: {:wb => wb}

app/views/admin/registrations/index.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb = xlsx_package.workbook
 wb.add_worksheet(name: 'registrations') do |sheet|
   bold_style = wb.styles.add_style(b: true)

app/views/admin/tracks/_all_tracks.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb.add_worksheet(name: 'all tracks') do |sheet|
   bold_style = wb.styles.add_style(b: true)
   wrap_text = wb.styles.add_style alignment: {wrap_text: true}

app/views/admin/tracks/_confirmed_tracks.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb.add_worksheet(name: 'all tracks') do |sheet|
   bold_style = wb.styles.add_style(b: true)
   wrap_text = wb.styles.add_style alignment: {wrap_text: true}

app/views/admin/tracks/tracks.xlsx.axlsx

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 wb = xlsx_package.workbook
 if @track_export_option == 'confirmed'
   render partial: 'confirmed_tracks', locals: { wb: wb }