Fix `Lint/SymbolConversion` cop (#28175)

app/models/concerns/remotable.rb

@@ -5,7 +5,7 @@ module Remotable
 
   class_methods do
     def remotable_attachment(attachment_name, limit, suppress_errors: true, download_on_assign: true, attribute_name: nil)
-      attribute_name ||= "#{attachment_name}_remote_url".to_sym
+      attribute_name ||= :"#{attachment_name}_remote_url"
 
       define_method("download_#{attachment_name}!") do |url = nil|
         url ||= self[attribute_name]

app/models/user_settings/setting.rb

@@ -62,7 +62,7 @@ class UserSettings::Setting
 
   def key
     if namespace
-      "#{namespace}.#{name}".to_sym
+      :"#{namespace}.#{name}"
     else
       name
     end

config/deploy.rb

@@ -20,7 +20,7 @@ namespace :systemd do
   SYSTEMD_SERVICES.each do |service|
     SERVICE_ACTIONS.each do |action|
       desc "Perform a #{action} on #{service} service"
-      task "#{service}:#{action}".to_sym do
+      task :"#{service}:#{action}" do
         on roles(:app) do
           # runs e.g. "sudo restart mastodon-sidekiq.service"
           sudo :systemctl, action, "#{fetch(:application)}-#{service}.service"

spec/models/concerns/remotable_spec.rb

@@ -31,7 +31,7 @@ RSpec.describe Remotable do
     end
   end
 
-  let(:attribute_name) { "#{hoge}_remote_url".to_sym }
+  let(:attribute_name) { :"#{hoge}_remote_url" }
   let(:code)           { 200 }
   let(:file)           { 'filename="foo.txt"' }
   let(:foo)            { foo_class.new }