Update documentation for IO.Compression (#120840)

Follow-up PR for #120495
Fills in missing return tags

Author: alinpahontu2912

src/libraries/System.IO.Compression.ZipFile/src/System/IO/Compression/ZipFile.Create.Async.cs

@@ -264,6 +264,7 @@ public static Task CreateFromDirectoryAsync(string sourceDirectoryName, string d
     /// be included at the root of the archive. <code>false</code> to indicate that the files and directories in <code>sourceDirectoryName</code>
     /// should be included directly in the archive.</param>
     /// <param name="cancellationToken">The cancellation token to monitor for cancellation requests.</param>
+    /// <returns>A task that represents the asynchronous create operation. The task completes when the archive has been written to disk.</returns>
     public static Task CreateFromDirectoryAsync(string sourceDirectoryName, string destinationArchiveFileName, CompressionLevel compressionLevel, bool includeBaseDirectory, CancellationToken cancellationToken = default) =>
         DoCreateFromDirectoryAsync(sourceDirectoryName, destinationArchiveFileName, compressionLevel, includeBaseDirectory, entryNameEncoding: null, cancellationToken);
 
@@ -335,6 +336,7 @@ public static Task CreateFromDirectoryAsync(string sourceDirectoryName, string d
     ///     otherwise an <see cref="ArgumentException"/> is thrown.</para>
     /// </param>
     /// <param name="cancellationToken">The cancellation token to monitor for cancellation requests.</param>
+    /// <returns>A task that represents the asynchronous create operation. The task completes when the archive has been written to disk.</returns>
     public static Task CreateFromDirectoryAsync(string sourceDirectoryName, string destinationArchiveFileName,
                                            CompressionLevel compressionLevel, bool includeBaseDirectory, Encoding? entryNameEncoding, CancellationToken cancellationToken = default) =>
         DoCreateFromDirectoryAsync(sourceDirectoryName, destinationArchiveFileName, compressionLevel, includeBaseDirectory, entryNameEncoding, cancellationToken);
@@ -392,6 +394,7 @@ public static Task CreateFromDirectoryAsync(string sourceDirectoryName, Stream d
     /// <exception cref="NotSupportedException"><paramref name="sourceDirectoryName" /> contains an invalid format.</exception>
     /// <exception cref="ArgumentOutOfRangeException"><paramref name="compressionLevel"/> is not a valid <see cref="CompressionLevel"/> value.</exception>
     /// <exception cref="OperationCanceledException">An asynchronous operation is cancelled.</exception>
+    /// <returns>A task that represents the asynchronous create operation. The task completes when the archive has been written to the specified stream.</returns>
     public static Task CreateFromDirectoryAsync(string sourceDirectoryName, Stream destination, CompressionLevel compressionLevel, bool includeBaseDirectory, CancellationToken cancellationToken = default) =>
         DoCreateFromDirectoryAsync(sourceDirectoryName, destination, compressionLevel, includeBaseDirectory, entryNameEncoding: null, cancellationToken);
 
@@ -422,6 +425,7 @@ public static Task CreateFromDirectoryAsync(string sourceDirectoryName, Stream d
     /// <exception cref="NotSupportedException"><paramref name="sourceDirectoryName" /> contains an invalid format.</exception>
     /// <exception cref="ArgumentOutOfRangeException"><paramref name="compressionLevel"/> is not a valid <see cref="CompressionLevel"/> value.</exception>
     /// <exception cref="OperationCanceledException">An asynchronous operation is cancelled.</exception>
+    /// <returns>A task that represents the asynchronous create operation. The task completes when the archive has been written to the specified stream.</returns>
     public static Task CreateFromDirectoryAsync(string sourceDirectoryName, Stream destination,
                                            CompressionLevel compressionLevel, bool includeBaseDirectory, Encoding? entryNameEncoding, CancellationToken cancellationToken = default) =>
         DoCreateFromDirectoryAsync(sourceDirectoryName, destination, compressionLevel, includeBaseDirectory, entryNameEncoding, cancellationToken);

src/libraries/System.IO.Compression.ZipFile/src/System/IO/Compression/ZipFile.Extract.Async.cs

@@ -133,6 +133,7 @@ public static Task ExtractToDirectoryAsync(string sourceArchiveFileName, string
     ///     otherwise an <see cref="ArgumentException"/> is thrown.</para>
     /// </param>
     /// <param name="cancellationToken">The cancellation token to monitor for cancellation requests.</param>
+    /// <returns>A task that represents the asynchronous extract operation. The task completes when all entries have been extracted or an error occurs.</returns>
     public static Task ExtractToDirectoryAsync(string sourceArchiveFileName, string destinationDirectoryName, Encoding? entryNameEncoding, CancellationToken cancellationToken = default) =>
         ExtractToDirectoryAsync(sourceArchiveFileName, destinationDirectoryName, entryNameEncoding: entryNameEncoding, overwriteFiles: false, cancellationToken);
 
@@ -231,6 +232,7 @@ public static async Task ExtractToDirectoryAsync(string sourceArchiveFileName, s
     /// -or-
     /// An archive entry was compressed by using a compression method that is not supported.</exception>
     /// <exception cref="OperationCanceledException">An asynchronous operation is cancelled.</exception>
+    /// <returns>A task that represents the asynchronous extract operation. The task completes when all entries have been extracted or an error occurs.</returns>
     public static Task ExtractToDirectoryAsync(Stream source, string destinationDirectoryName, CancellationToken cancellationToken = default) =>
         ExtractToDirectoryAsync(source, destinationDirectoryName, entryNameEncoding: null, overwriteFiles: false, cancellationToken);
 
@@ -262,6 +264,7 @@ public static Task ExtractToDirectoryAsync(Stream source, string destinationDire
     /// -or-
     /// An archive entry was compressed by using a compression method that is not supported.</exception>
     /// <exception cref="OperationCanceledException">An asynchronous operation is cancelled.</exception>
+    /// <returns>A task that represents the asynchronous extract operation. The task completes when all entries have been extracted or an error occurs.</returns>
     public static Task ExtractToDirectoryAsync(Stream source, string destinationDirectoryName, bool overwriteFiles, CancellationToken cancellationToken = default) =>
         ExtractToDirectoryAsync(source, destinationDirectoryName, entryNameEncoding: null, overwriteFiles: overwriteFiles, cancellationToken);
 
@@ -301,6 +304,7 @@ public static Task ExtractToDirectoryAsync(Stream source, string destinationDire
     /// -or-
     /// An archive entry was compressed by using a compression method that is not supported.</exception>
     /// <exception cref="OperationCanceledException">An asynchronous operation is cancelled.</exception>
+    /// <returns>A task that represents the asynchronous extract operation. The task completes when all entries have been extracted or an error occurs.</returns>
     public static Task ExtractToDirectoryAsync(Stream source, string destinationDirectoryName, Encoding? entryNameEncoding, CancellationToken cancellationToken = default) =>
         ExtractToDirectoryAsync(source, destinationDirectoryName, entryNameEncoding: entryNameEncoding, overwriteFiles: false, cancellationToken);
 
@@ -341,6 +345,7 @@ public static Task ExtractToDirectoryAsync(Stream source, string destinationDire
     /// -or-
     /// An archive entry was compressed by using a compression method that is not supported.</exception>
     /// <exception cref="OperationCanceledException">An asynchronous operation is cancelled.</exception>
+    /// <returns>A task that represents the asynchronous extract operation. The task completes when all entries have been extracted or an error occurs.</returns>
     public static async Task ExtractToDirectoryAsync(Stream source, string destinationDirectoryName, Encoding? entryNameEncoding, bool overwriteFiles, CancellationToken cancellationToken = default)
     {
         cancellationToken.ThrowIfCancellationRequested();