Add XML docs to core packages

src/Microsoft.AspNetCore.SpaServices/Prerendering/RenderToStringResult.cs

@@ -2,10 +2,28 @@ using Newtonsoft.Json.Linq;
 
 namespace Microsoft.AspNetCore.SpaServices.Prerendering
 {
+    /// <summary>
+    /// Describes the prerendering result returned by JavaScript code.
+    /// </summary>
     public class RenderToStringResult
     {
+        /// <summary>
+        /// If set, specifies JSON-serializable data that should be added as a set of global JavaScript variables in the document.
+        /// This can be used to transfer arbitrary data from server-side prerendering code to client-side code (for example, to
+        /// transfer the state of a Redux store).
+        /// </summary>
         public JObject Globals { get; set; }
+
+        /// <summary>
+        /// The HTML generated by the prerendering logic.
+        /// </summary>
         public string Html { get; set; }
+
+        /// <summary>
+        /// If set, specifies that instead of rendering HTML, the response should be an HTTP redirection to this URL.
+        /// This can be used if the prerendering code determines that the requested URL would lead to a redirection according
+        /// to the SPA's routing configuration.
+        /// </summary>
         public string RedirectUrl { get; set; }
     }
 }