docs: Add Windows Server 2022 as affected IIS target

[nastoo]

Add Windows Server 2022 as confirmed affected IIS target

Summary

• Adds Windows Server 2022 Standard (Build 20348.587, http.sys 10.0.20348.1) as a confirmed affected target alongside
  Windows Server 2025
• Updates the affected target tables in README.md and blog.md to list both Windows Server 2022, 2025
• Restructures the Setup section in microsoft-iis/README.md to list each confirmed build as its own bullet point, with
  a shared note that all targets require IIS with HTTPS on port 443 in default configuration

Test plan

• Verify microsoft-iis/README.md setup section renders correctly with the nested bullet format
• Confirm the top-level README.md and blog.md tables correctly reflect both affected versions