Add non-sdk project heading to dotnet nuget why docs (#47589)

Author: zivkan

docs/core/tools/dotnet-nuget-why.md

@@ -24,14 +24,16 @@ dotnet nuget why -h|--help
 
 The `dotnet nuget why` command shows the dependency graph for a particular package for a given project or solution.
 
-Starting from the .NET 9 SDK, it's possible to pass a NuGet assets file in place of the project file, in order to use the command with projects that can't be restored with the .NET SDK.
-First, restore the project in Visual Studio, or `msbuild.exe`.
-By default the assets file is in the project's `obj\` directory, but you can find the location with `msbuild.exe path\to\project.proj -getProperty:ProjectAssetsFile`.
-Finally, run `dotnet nuget why path\to\project.assets.json SomePackage`.
-
 Starting with version 9.0.200, the command introduces support for runtime identifier (RID) specific packages by generating separate dependency trees for each RID and framework combination.
 For example, if a project targets `net9.0` with the `win-x64` RID, the command generates trees for `net9.0/win-x64` and `net9.0`.
 
+### Older project format
+
+To use the command with projects that can't be restored with the .NET SDK, you can pass a NuGet assets file in place of the project file (starting with the .NET 9 SDK):
+
+1. First, restore the project in Visual Studio or using `msbuild.exe`. By default, the assets file is in the project's `obj\` directory, but you can find the location with `msbuild.exe path\to\project.proj -getProperty:ProjectAssetsFile`.
+2. Run `dotnet nuget why path\to\project.assets.json SomePackage`.
+
 ## Arguments
 
 - **`PROJECT|SOLUTION`**