Adding comments

Author: Nirjan Chapagain

src/VirtualClient/VirtualClient.Dependencies/CertificateInstallation.cs

@@ -82,7 +82,7 @@ public bool WithPrivateKey
         }
 
         /// <summary>
-        /// 
+        /// Gets the directory where the certificate will be exported. If not provided, the certificate will not be exported to a file.
         /// </summary>
         public string CertificateDownloadDir
         {

src/VirtualClient/VirtualClient.Main/OptionFactory.cs

@@ -665,8 +665,8 @@ public static Option CreateCertificateDownloadDirectoryOption(bool required = fa
             Option<string> option = new Option<string>(new string[] { "--certificateDownloadDir", "--certDownloadDir" })
             {
                 Name = "CertificateDownloadDir",
-                Description = "Set (optional) directory path which certificates downloaded from Key Vault can be saved.",
-                ArgumentHelpName = "tid",
+                Description = "Defines the directory where certificates downloaded from Key Vault will be saved.",
+                ArgumentHelpName = "path",
                 AllowMultipleArgumentsPerToken = false
             };