fix(docs): Correct default rollForward policy in global.json documentation

[nileshsheth]

📜 Description

This PR updates the global-json.md documentation to correctly reflect the default rollForward behavior in the .NET SDK.

🔍 Issue

The documentation previously stated:

If no rollForward value is set, it uses latestPatch as the default rollForward policy.

However, based on actual SDK behavior and tracing logs (see dotnet/core-setup#6953), the default policy is actually patch, not latestPatch.

🛠 Fix

• Updated the incorrect statement in global-json.md to specify patch as the default rollForward policy.
• This aligns the documentation with the real behavior of the .NET SDK.

📎 Related Issues

• Fixes fixed Visual Studio Code branding #2246 (if an issue exists in the repo).
• References Implement roll-forward policies for .NET Core SDK resolution. core-setup#6953.

📸 Verification

✅ The demo provided in the issue confirms that patch is the default policy.
✅ Tracing logs explicitly state rollForward = 'patch'.

📂 Files Changed

• docs/core/tools/global-json.md

🔗 Additional Context

For backwards compatibility, the SDK defaults to patch when rollForward is not specified in global.json. This update ensures that the documentation accurately reflects this behavior.

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Internal previews

📄 File	🔗 Preview link
docs/core/tools/global-json.md	global.json overview