Added whitespace

docs/en/reference/configuration.rst

@@ -250,7 +250,7 @@ pdo\_pgsql
 -  ``dbname`` (string): Name of the database/schema to connect to.
 -  ``charset`` (string): The charset used when connecting to the
    database.
--  ``default_dbname`` (string): Override the default database(postgres)
+-  ``default_dbname`` (string): Override the default database (postgres)
    to connect to.
 -  ``sslmode`` (string): Determines whether or with what priority
    a SSL TCP/IP connection will be negotiated with the server.