Add XML docs to core packages

src/Microsoft.AspNetCore.NodeServices/HostingModels/NodeInvocationException.cs

@@ -2,15 +2,33 @@ using System;
 
 namespace Microsoft.AspNetCore.NodeServices.HostingModels
 {
+    /// <summary>
+    /// Represents an exception caused by invoking Node.js code.
+    /// </summary>
     public class NodeInvocationException : Exception
     {
+        /// <summary>
+        /// If true, indicates that the invocation failed because the Node.js instance could not be reached. For example,
+        /// it might have already shut down or previously crashed.
+        /// </summary>
         public bool NodeInstanceUnavailable { get; private set; }
 
+        /// <summary>
+        /// Creates a new instance of <see cref="NodeInvocationException"/>.
+        /// </summary>
+        /// <param name="message">A description of the exception.</param>
+        /// <param name="details">Additional information, such as a Node.js stack trace, representing the exception.</param>
         public NodeInvocationException(string message, string details)
             : base(message + Environment.NewLine + details)
         {
         }
 
+        /// <summary>
+        /// Creates a new instance of <see cref="NodeInvocationException"/>.
+        /// </summary>
+        /// <param name="message">A description of the exception.</param>
+        /// <param name="details">Additional information, such as a Node.js stack trace, representing the exception.</param>
+        /// <param name="nodeInstanceUnavailable">Specifies a value for the <see cref="NodeInstanceUnavailable"/> flag.</param>
         public NodeInvocationException(string message, string details, bool nodeInstanceUnavailable)
             : this(message, details)
         {