Fix test name

Wow this is embarrassing. I literally named this FIXME so I'd remember
to give it some name that made sense and then I totally did not.

railties/test/application/rake/dbs_test.rb

@@ -173,7 +173,7 @@ def db_create_with_warning(expected_database)
         db_create_and_drop("db/development.sqlite3", environment_loaded: false)
       end
 
-      test "db:create and db:drop dont raise errors when loading YAML with FIXME ERB" do
+      test "db:create and db:drop dont raise errors when loading YAML with single-line ERB" do
         app_file "config/database.yml", <<-YAML
           development:
             <%= Rails.application.config.database ? 'database: db/development.sqlite3' : 'database: db/development.sqlite3' %>