examples: add leapsecmode to chrony.conf examples

examples/chrony.conf.example2

@@ -34,6 +34,9 @@ rtcsync
 # Save NTS keys and cookies.
 ntsdumpdir /var/lib/chrony
 
+# Insert/delete leap seconds by slewing instead of stepping.
+#leapsecmode slew
+
 # Get TAI-UTC offset and leap seconds from the system tz database.
 #leapsectz right/UTC
 

examples/chrony.conf.example3

@@ -145,6 +145,18 @@ ntsdumpdir /var/lib/chrony
 
 ! makestep 1.0 3
 
+#######################################################################
+### LEAP SECONDS
+# A leap second is an occasional one-second correction of the UTC
+# time scale.  By default, chronyd tells the kernel to insert/delete
+# the leap second, which makes a backward/forward step to correct the
+# clock for it.  As with the makestep directive, this jump can upset
+# some applications.  If you prefer chronyd to make a gradual
+# correction, causing the clock to be off for a longer time, uncomment
+# the following line.
+
+! leapsecmode slew
+
 #######################################################################
 ### LOGGING
 # If you want to log information about the time measurements chronyd has