feat: Improve Chapter 2 with the 'ls -a' flag

[dwmkerr]

Comment from the share on LinkedIn:

One thing I would add is to quickly mention hidden files when introducing the -a flag for ls, since users might come across those at this point and wonder what they are.

Great suggestion from here: https://www.linkedin.com/feed/update/urn%3Ali%3Aactivity%3A6660383783935705088/?commentUrn=urn%3Ali%3Acomment%3A%28activity%3A6660383783935705088%2C6663312143833804800%29&midToken=AQG-nz-C47s2lg&trk=eml-email_notification_single_commented_on_your_update_01-notifications-1-hero%7Ecard%7Efeed&trkEmail=eml-email_notification_single_commented_on_your_update_01-notifications-1-hero%7Ecard%7Efeed-null-2q7p3b%7Ek9ti6xyf%7E2n-null-voyagerOffline