Update RuntimeInformation.xml (#4973)

Author: gewarren

xml/System.Runtime.InteropServices/RuntimeInformation.xml

@@ -65,19 +65,19 @@
         <ReturnType>System.String</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>Returns a string that indicates the name of the .NET installation on which an app is running.</summary>
+        <summary>Gets the name of the .NET installation on which an app is running.</summary>
         <value>The name of the .NET installation on which the app is running.</value>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
-## Remarks  
- The property returns a string that starts with one of the following and indicates the name of the currently executing .NET implementation, usually followed by the current version:  
-  
--   ".NET Core".  
-  
--   ".NET Framework".  
-  
--   ".NET Native".  
+## Remarks
+
+The property returns a string that indicates the name of the currently executing .NET implementation. The string starts with one of the following descriptions, usually followed by the current version:  
+
+- ".NET" (for .NET 5.0 and later versions)
+- ".NET Core" (for .NET Core 1.0 - 3.1)
+- ".NET Framework"
+- ".NET Native"
   
  ]]></format>
         </remarks>
@@ -265,17 +265,18 @@
         <ReturnType>System.String</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>Returns an opaque string that identifies the platform on which an app is running.</summary>
-        <value>To be added.</value>
+        <summary>Gets the platform on which an app is running.</summary>
+        <value>An opaque string that identifies the platform on which the app is running.</value>
         <remarks>
           <format type="text/markdown"><![CDATA[
 
 ## Remarks
 
 This property returns a string that identifies the operating system, typically including the version and processor architecture of the currently executing process.
- Since this string is opaque, it is not recommended to parse the string into its constituent parts.
+
+Since this string is opaque, it's not recommended to parse the string into its constituent parts.
  
- For more information, see https://docs.microsoft.com/dotnet/core/rid-catalog.
+For more information, see [.NET Core RID catalog](/dotnet/core/rid-catalog).
 
           ]]></format>
         </remarks>