doc/muxers: remove confusing example for segment muxer option clocktime_wrap_duration

Detecting a leap second depends on a lot of things, segment time, segment
offset, system leap second implementation, the removed part is a huge
simplification which can be misleading, so it is best to remove it.

Signed-off-by: Marton Balint <cus@passwd.hu>

doc/muxers.texi

@@ -1441,9 +1441,6 @@ within the specified duration after the segmenting clock time. This way you
 can make the segmenter more resilient to backward local time jumps, such as
 leap seconds or transition to standard time from daylight savings time.
 
-Assuming that the delay between the packets of your source is less than 0.5
-second you can detect a leap second by specifying 0.5 as the duration.
-
 Default is the maximum possible duration which means starting a new segment
 regardless of the elapsed time since the last clock time.