Fix doc comment variable reference

src/Datasource/ConnectionManager.php

@@ -80,7 +80,7 @@ class ConnectionManager {
  * If an array is given, the parsed dsn will be merged into this array. Note that querystring
  * arguments are also parsed and set as values in the returned configuration.
  *
- * @param string|array $key Either a DSN or an array with a `dsn` key mapping to a string dsn
+ * @param string|array $config An array with a `dsn` key mapping to a string dsn
  * @return mixed null when adding configuration and an array of configuration data when reading.
  */
 	public static function parseDsn($config) {