Fix new method name in DatabaseConfig#config deprecation message

Author: eugeneius

activerecord/lib/active_record/database_configurations/hash_config.rb

@@ -33,7 +33,7 @@ def initialize(env_name, name, configuration_hash)
       end
 
       def config
-        ActiveSupport::Deprecation.warn("DatabaseConfig#config will be removed in 7.0.0 in favor of DatabaseConfigurations#configuration_hash which returns a hash with symbol keys")
+        ActiveSupport::Deprecation.warn("DatabaseConfig#config will be removed in 7.0.0 in favor of DatabaseConfig#configuration_hash which returns a hash with symbol keys")
         configuration_hash.stringify_keys
       end