Alias Header number -> blockNumber (#760)

packages/types/src/type/Header.ts

@@ -68,6 +68,13 @@ export default class Header extends Struct {
     );
   }
 
+  /**
+   * @description Alias for `blockNumber` (this is displayed in JSON)
+   */
+  get number (): BlockNumber {
+    return this.blockNumber;
+  }
+
   /**
    * @description The wrapped parent as a [[Hash]]
    */