Doc: Updated typos on the 0-zarf-overview.md page.

[TheFutonEng]

Description

I found some typos reviewing the Zarf docs site, specifically the overview page.

Related Issue

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist before merging

• Tests have been added/updated as necessary (add the needs-tests label)
• Documentation has been updated as necessary (add the needs-docs label)
• An ADR has been written as necessary (add the needs-adr label) [ 1 2 3 ]
• (Optional) Changes have been linted locally with golangci-lint. (NOTE: We haven't turned on lint checks in the pipeline yet so linting may be hard if it shows a lot of lint errors in places that weren't touched by changes. Thus, linting is optional right now.)

[YrrepNoj]

Thanks for the updates. I'll meet up with you later today to sort of the GPG key stuff so we can get this merged in :)