add unix config section description

Signed-off-by: R4SAS <r4sas@i2pmail.org>

docs/user-guide/configuration.md

@@ -265,6 +265,17 @@ Option                                 | Description
 meshnets.yggdrasil                     | Support transports through the Yggdrasil
 meshnets.yggaddress                    | Local Yggdrasil's address to publish
 
+### UNIX-specific
+
+Option                                 | Description
+-------------------------------------- | --------------------------------------
+unix.handle_sigtstp                    | Handle SIGTSTP and SIGCONT signals. Disabled by default
+
+`handle_sigtstp` enables handling of SIGTSTP and SIGCONT signals. (~will be added in 2.43.0~)
+
+SIGTSTP can be called using Ctrl+Z in terminal with running i2pd in it or by `kill` command. When signal recveived, i2pd will switch to offline mode and stop sending traffic and cleaning of netDb. All active tunnels will be frozen.
+
+To restore network connectivity you need to send SIGCONT signal to proccess. Tunnels will be cleared if they should expire during the frozen state time and new ones will be built.
 
 Local addressbook
 -----------------