Backport XML documentation for WebProxy and IWebProxyScript

src/libraries/System.Net.WebProxy/src/System.Net.WebProxy.csproj

@@ -3,7 +3,6 @@
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);$(NetCoreAppCurrent)-browser;$(NetCoreAppCurrent)-wasi</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>
   </PropertyGroup>
 
   <ItemGroup>

src/libraries/System.Net.WebProxy/src/System/Net/IWebProxyScript.cs

@@ -3,10 +3,39 @@
 
 namespace System.Net
 {
+    /// <summary>
+    /// Provides the base interface to load and execute scripts for automatic proxy detection.
+    /// </summary>
     public interface IWebProxyScript
     {
+        /// <summary>
+        /// Closes a script.
+        /// </summary>
         void Close();
+
+        /// <summary>
+        /// Loads a script.
+        /// </summary>
+        /// <param name="scriptLocation">The URI that identifies the location of the proxy auto-configuration script.</param>
+        /// <param name="script">The script content to load and prepare for execution.</param>
+        /// <param name="helperType">The type that provides helper methods or services available to the script at runtime.</param>
+        /// <returns>A <see cref="bool"/> indicating whether the script was successfully loaded.</returns>
         bool Load(Uri scriptLocation, string script, Type helperType);
+
+        /// <summary>
+        /// Runs a script.
+        /// </summary>
+        /// <param name="url">The destination URL for which proxy information is requested.</param>
+        /// <param name="host">The host name associated with the destination URL.</param>
+        /// <returns>
+        /// A <see cref="string"/> that describes how to connect to the destination, such as a proxy configuration directive (for example, <c>"DIRECT"</c> or <c>"PROXY host:port"</c>).
+        /// </returns>
+        /// <remarks>
+        /// <para>
+        /// When the object is run, it might need to run the WPAD (Web Proxy Automatic Detection) protocol to detect whether a proxy is required for reaching the destination URL.
+        /// During this process, the system downloads and compiles the PAC (Proxy Auto-Configuration) script in memory and tries to execute the FindProxyForURL function as per the PAC specification.
+        /// </para>
+        /// </remarks>
         string Run(string url, string host);
     }
 }