Added reference to user auto-detect method

documentation/modules/exploit/linux/http/fortinet_authentication_bypass_cve_2022_40684.md

@@ -19,8 +19,8 @@ The following products are affected:
 ### Exploitation
 
 This module will abuse the authentication bypass vulnerability in the affected products to add a new ssh public
-key in the authorized keys of the target user and then connect over ssh to the target system. If no ssh private
-key is provided this module will automatically generate one.
+key in the authorized keys of the target user (if no user is provied it'll try to detect it) and then connect
+over ssh to the target system (if no ssh private key is provided this module will automatically generate one).
 
 To do so it will add the following header in all HTTP requests:
 ```