glances: add option placeholders and exit key (#15963)

Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>

pages/common/glances.md

@@ -9,16 +9,24 @@
 
 - Run in web server mode to show results in browser:
 
-`glances -w`
+`glances {{[-w|--webserver]}}`
 
 - Run in server mode to allow connections from other Glances clients:
 
-`glances -s`
+`glances {{[-s|--server]}}`
 
 - Connect to a Glances server:
 
-`glances -c {{hostname}}`
+`glances {{[-c|--client]}} {{hostname}}`
 
 - Require a password in (web) server mode:
 
-`glances -s --password`
+`glances {{[-s|--server]}} --password`
+
+- Exit Glances:
+
+`<q>`
+
+- Display help:
+
+`glances {{[-h|--help]}}`