[WIP] Add information on certificate format in documentation

[Copilot]

Thanks for assigning this issue to me. I'm starting to work on it and will keep this PR's description up to date as I form a plan and make progress.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>In what format are these certificates?</issue_title>
<issue_description>Without information on what format these certificates are in this documentation is not very helpful.

A remark, that this returns a certificate chain and not a single certificate might also be helpful.

---

Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: 953a303a-4854-66f5-1140-8052bf8bc652
• Version Independent ID: 87ff3b8d-f12a-6403-e4d3-1006a190f8d9
• Content: HardwareToken.Certificate Property (Windows.System.Profile) - Windows UWP applications
• Content Source: winrt-api-build/xml/Windows.System.Profile/HardwareToken.xml
• Product: uwp
• Technology: winrt-reference
• GitHub Login: @hickeys
• Microsoft Alias: hickeys</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes In what format are these certificates? #1701

---

💬 Send tasks to Copilot coding agent from Slack and Teams to turn conversations into code. Copilot posts an update in your thread when it's finished.