docs: Remove reference to poll-period in apply reference doc (#3760)

Author: mortent

internal/docs/generated/livedocs/docs.go

@@ -78,10 +78,6 @@ PKG_PATH | -:
 
   The default value is ‘events’.
 
---poll-period:
-  The frequency with which the cluster will be polled to determine
-  the status of the applied resources. The default value is 2 seconds.
-
 --prune-propagation-policy:
   The propagation policy that should be used when pruning resources. The
   default value here is 'Background'. The other options are 'Foreground' and 'Orphan'.