typo on iron introduction page

#### Context

I think there is an typo on explaning the seal process.

pagelink : https://hapi.dev/module/iron/#introduction

The example said mac the encrypted object with **salt E** and iv.

Following the iron code linked below, HACM key(**Key I**) is used to make mac instaed of salt E. So if I understood correctly, the sentence should be mac the encrypted object along with KeyI and iv.

https://github.com/hapijs/iron/blob/62e00b64bd405a2c8bc773328774da9f7cc92d3c/lib/index.js#L229