conf: Document accepted number and time formats

src/swanctl/swanctl.conf.5.head.in

@@ -6,20 +6,11 @@ swanctl.conf is the configuration file used by the
 .BR swanctl (8)
 tool to load configurations and credentials into the strongSwan IKE daemon.
 
-For a description of the basic file syntax, including how to reference sections
-or split the configuration in multiple files by including other files, refer to
+For a description of the basic file syntax, including numer/time formats, or how
+to reference sections or split the configuration in multiple files by including
+other files, refer to
 .BR strongswan.conf (5).
 
-.SH TIME FORMATS
-For all options that define a time, the time is specified in seconds. The
-.RI "" "s" ","
-.RI "" "m" ","
-.RI "" "h" ""
-and
-.RI "" "d" ""
-suffixes explicitly define the units for seconds, minutes, hours and days,
-respectively.
-
 .SH SETTINGS
 The following settings can be used to configure connections, credentials and
 pools.