message: surrounding diagram with pre tags
diff: @@ -17,6 +17,7 @@ interface AMOscillatorOptions extends ToneOscillatorOptions {
  * two oscillators, one which modulators the other's amplitude
  * through a gain node.
  *
  + * <pre>
  * +-------------+ +----------+
  * | Carrier Osc +>------> GainNode |
  * +-------------+ | +--->Output
  @@ -24,6 +25,7 @@ interface AMOscillatorOptions extends ToneOscillatorOptions {
  * +---------------+ | +----------+
  * | Modulator Osc +>---+
  * +---------------+
  + * </pre>
  *
  * @param frequency The starting frequency of the oscillator.
  * @param type The type of the carrier oscillator.
  