Fix module desc

Author: nixawk

modules/exploits/multi/http/struts_dmi_rest_exec.rb

@@ -17,8 +17,8 @@ def initialize(info = {})
       'Description'    => %q{
         This module exploits a remote command execution vulnerability in Apache Struts
         version between 2.3.20 and 2.3.28 (except 2.3.20.2 and 2.3.24.2). Remote Code
-        Execution can be performed via method: prefix when Dynamic Method Invocation
-        is enabled.
+        Execution can be performed when using REST Plugin with ! operator when
+        Dynamic Method Invocation is enabled.
       },
       'Author'         => [
         'Nixawk' # original metasploit module