TelnetServer: Remove declarations for non-existent methods

Author: https://github.com/AtkinsSJ
Commit: https://github.com/SerenityOS/serenity/commit/990f1c799e
Pull-request: https://github.com/SerenityOS/serenity/pull/17203
Reviewed-by: https://github.com/linusg ✅

Userland/Services/TelnetServer/Parser.h

@@ -31,8 +31,6 @@ protected:
         Error,
     };
 
-    void write(DeprecatedString const& str);
-
 private:
     State m_state { State::Free };
     u8 m_command { 0 };