Fix the number of progressor steps in the relay_progress example

The steps= argument of progressor did not match the actual number of
emitted progressions or rather the sum of their `amount=`s (there are progressions with amount=0) as well in slow_sum()

Author: mlell

incl/progress_aggregator.R

@@ -3,11 +3,11 @@ library(progressr)
 message("progress_aggregator() ...")
 
 with_progress({
-  progress <- progressor(steps = 4L)
+  progress <- progressor(steps = 8L)
   relay_progress <- progress_aggregator(progress)
   progress()
-  relay_progress(slow_sum(1:3))
-  relay_progress(slow_sum(1:10))
+  relay_progress(slow_sum(1:2))
+  relay_progress(slow_sum(1:4))
   progress()
 })