Update docs for Environment.Version (dotnet#5196)

Author: MSDN-WhiteKnight

xml/System/Environment.xml

@@ -2499,15 +2499,17 @@ The following example creates environment variables for the <xref:System.Environ
           <format type="text/markdown"><![CDATA[
 
 ## Remarks
- For the .NET Framework Versions 4, 4.5, 4.5.1, and 4.5.2, the <xref:System.Environment.Version%2A?displayProperty=nameWithType> property returns a <xref:System.Version> object whose string representation has the form `4.0.30319.xxxxx`. For the .NET Framework 4.6 and later versions, it has the form `4.0.30319.42000`.
+  For .NET Core 3.x and .NET 5+, the <xref:System.Environment.Version%2A?displayProperty=nameWithType> property returns the .NET runtime version number.
+
+  For the .NET Framework Versions 4, 4.5, 4.5.1, and 4.5.2, the <xref:System.Environment.Version%2A?displayProperty=nameWithType> property returns a <xref:System.Version> object whose string representation has the form `4.0.30319.xxxxx`. For the .NET Framework 4.6 and later versions, and .NET Core versions before 3.0, it has the form `4.0.30319.42000`.
 
 > [!WARNING]
 > For the .NET Framework 4.5 and later, we do not recommend using the <xref:System.Environment.Version%2A> property to detect the version of the runtime; instead, you can determine the version of the common language runtime by querying the registry. For more information, see [How to: Determine Which .NET Framework Versions Are Installed](/dotnet/framework/migration-guide/how-to-determine-which-versions-are-installed).
 
  For more information about the version of the common language runtime that is installed with each version of the .NET Framework, see [Versions and Dependencies](/dotnet/framework/migration-guide/versions-and-dependencies).
 
 ## Examples
- The following example displays the version of the common language runtime. (The version is omitted from the example output for security reasons.)
+ The following example displays the version of the common language runtime.
 
  [!code-cpp[Environment.Version#1](~/samples/snippets/cpp/VS_Snippets_CLR/Environment.Version/CPP/version.cpp#1)]
  [!code-csharp[Environment.Version#1](~/samples/snippets/csharp/VS_Snippets_CLR/Environment.Version/CS/version.cs#1)]