updated documentation for midikeys

packages/midi/midi.mjs

@@ -536,6 +536,9 @@ export async function midin(input) {
  *
  * The note length is fixed as Superdough is not currently set up for undetermined
  * note durations
+ * 
+ * The 'midichan' control value contains the number of the channel the note is coming from
+ * so it could be filtered or manipulated further in the chain.
  *
  * @name midikeys
  * @tags external_io, midi
@@ -552,6 +555,10 @@ export async function midin(input) {
  *   .s("saw")
  *   .add(note(rand.mul(0.3)))
  *   .lpf(1000).lpe(2).room(0.5)
+ * @example
+ * // discard all notes not coming out from midi channel 2
+ * const kb = await midikeys('Arturia KeyStep 32')
+ * kb().filterValues(v=>v.midichan==2).s("tri")
  */
 const kHaps = {};
 const kListeners = {};