appsettings.json and appsettings.<Environment>.json tracked by git are
listed under Repos, keys named as .NET names them (ConnectionStrings:Default).
- The secret patterns pick the keys, the rest hidden, with
dotnet.secretPatterns for .NET files' own.
- An App Service Key Vault reference, @Microsoft.KeyVault(…), is marked
as a reference; a BOM at the start is fine.
- A .NET icon, themeable with dotnetColor.
