Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: jongalloway

CONTRIBUTING.md

@@ -107,7 +107,7 @@ If local testing behaves differently from the published NuGet package, check whe
 - Clear caches with `dotnet nuget locals all --clear`
 - Remove stale package folders such as `%USERPROFILE%\.nuget\packages\diagramforge\1.0.0`
 - Be careful with local sources like `artifacts/nupkg`, `--add-source`, or custom `NuGet.Config` entries
-- If needed, validate the published package explicitly with `RestoreSources=https://api.nuget.org/v3/index.json` and an isolated `RestorePackagesPath`
+- If needed, validate the published package explicitly by running `dotnet restore -p:RestoreSources=https://api.nuget.org/v3/index.json -p:RestorePackagesPath=./artifacts/isolated-packages` (or a similar isolated folder)
 
 Matching package ID and version do not guarantee matching bits. When diagnosing package issues, compare package or DLL hashes before assuming the published package is wrong.