add library(cont) to the list

README.md

@@ -341,6 +341,8 @@ The modules that ship with Scryer Prolog are also called
 * [`time`](src/prolog/lib/time.pl)
   `time/1` reports the CPU time of a goal. It is useful
   for measuring the performance of your code.
+* [`cont`](src/prolog/lib/cont.pl)
+  Provides *delimited continuations* via `reset/3` and `shift/1`.
 
 To read contents of external files, use `phrase_from_file/2` from
 [`library(pio)`](src/prolog/lib/pio.pl) to apply a DCG to