Updated FAQ (markdown)

FAQ.md

@@ -364,6 +364,8 @@ Case study:
 > B: Thanks, you have the true answer. The issue come from our Fortinet Client.
 
 # Command line output on Windows
+By default `rustdesk.exe` in command line on Windows has no output, you have to run it like below.
+
 - cmd.exe: `rustdesk.exe --get-id | more`
 
 - PowerShell: `rustdesk.exe --get-id | Out-String`