/**
 * Farts.
 *
 * @param {boolean=} opt_isWet Whether the fart is wet.
 */
function fart(opt_isWet) {
  if (opt_isWet) {
    console.log('pfffffpfpfpffffff?');
  } else {
    console.log('poooOOOot.');
  }
}

@@ -65,16 +65,27 @@
  is wet.
+ (Optional)
 %0A */%0Afun

Correct a glaring oversight in the documentation.