Autofix Rubocop Style/StringLiterals (#23695)

.rubocop_todo.yml

app/lib/webfinger.rb

db/migrate/20160305115639_add_devise_to_users.rb

db/migrate/20161122163057_remove_unneeded_indexes.rb

db/migrate/20170125145934_add_spoiler_text_to_statuses.rb

...grate/20171212195226_remove_duplicate_indexes_in_lists.rb

...ge_on_statuses_for_api_v1_accounts_account_id_statuses.rb

db/migrate/20180617162849_remove_unused_indexes.rb

.../20200521180606_encrypted_message_ids_to_timestamp_ids.rb

...e/20200622213645_media_attachment_ids_to_timestamp_ids.rb

db/migrate/20210306164523_account_ids_to_timestamp_ids.rb

lib/mastodon/emoji_cli.rb

lib/rails/engine_extensions.rb

lib/tasks/mastodon.rake

spec/controllers/admin/change_email_controller_spec.rb

spec/controllers/api/v1/streaming_controller_spec.rb

spec/controllers/application_controller_spec.rb

spec/controllers/auth/registrations_controller_spec.rb

spec/controllers/auth/sessions_controller_spec.rb

...trollers/oauth/authorized_applications_controller_spec.rb