[CONTENT-CHANGE] TLDR should list backups

[matkoniecz]

https://github.com/Lissy93/personal-security-checklist/blob/master/2_TLDR_Short_List.md really should mention "tested backups" as a critical point.

It protects against ransomware. It protects against data loss, one of the most important problems - both for typical people and ones under targeted attacks.

[Lissy93]

Definitely should, you are right. Will add it when I get a spare evening this week. Thanks for the recommendation :)