message: update: retry config setter docs
  update: timeout config setter docs
diff: @@ -285,7 +285,8 @@ impl<C, M> Builder<C, M, retry::Standard> {
  }
  impl<C, M> Builder<C, M> {
  - /// Set the standard retry policy's configuration.
  + /// Set the standard retry policy's configuration. When `config` is `None`,
  + /// the default retry policy will be used.
  pub fn set_retry_config(&mut self, config: Option<retry::Config>) -> &mut Self {
  let config = config.unwrap_or_default();
  self.retry_policy =
  @@ -299,7 +300,8 @@ impl<C, M> Builder<C, M> {
  self
  }
  - /// Set operation timeout config for the client.
  + /// Set operation timeout config for the client. If `operation_timeout_config` is
  + /// `None`, timeouts will be disabled.
  pub fn set_operation_timeout_config(
  &mut self,
  operation_timeout_config: Option<OperationTimeoutConfig>,
  