Removed dead code

Author: fubar-coder

src/FubarDev.FtpServer.Abstractions/ExtensionAnnouncementMode.cs

@@ -26,11 +26,6 @@ public interface IFtpCommandHandlerExtension : IFtpCommandBase
         [NotNull]
         string ExtensionFor { get; }
 
-        /// <summary>
-        /// Gets the extension announcement mode.
-        /// </summary>
-        ExtensionAnnouncementMode AnnouncementMode { get; }
-
         /// <summary>
         /// Called to initialize the connection data.
         /// </summary>

src/FubarDev.FtpServer.Abstractions/IFtpCommandHandlerExtension.cs

@@ -58,12 +58,6 @@ protected FtpCommandHandlerExtension([NotNull] string extensionFor, [NotNull] st
         /// <inheritdoc />
         public string ExtensionFor => _extensionFor ?? throw new InvalidOperationException("Obsolete property \"ExtensionFor\" called for a command handler extension.");
 
-        /// <summary>
-        /// Gets or sets the extension announcement mode.
-        /// </summary>
-        [Obsolete("Use the FtpCommandHandlerExtension attribute instead.")]
-        public ExtensionAnnouncementMode AnnouncementMode { get; set; } = ExtensionAnnouncementMode.Hidden;
-
         /// <summary>
         /// Gets or sets the FTP command context.
         /// </summary>