chore: more changeset documentation

Author: danigb

.changeset/flat-games-sneeze.md

@@ -41,3 +41,12 @@ Example:
 Chord.get("Cmaj7/B");
 Chord.get("Eb/D");
 ```
+
+### Feature: chord `notes`
+
+Now `notes` property of a chord are always pitch classes, there's a new function to get the actual notes:
+
+```js
+Chord.notes("Cmaj7", "C4"); // => ['C4', 'E4', 'G4', 'B4']
+Chord.notes("maj7", "D5"); // => ['D5', 'F#5', 'A5', 'C#6']
+```