Fix grammar after action(s)

Co-authored-by: Greg Lueck <[email protected]>

adoc/chapters/architecture.adoc

@@ -561,7 +561,7 @@ image::{images}/three-cg-three-queue.svg[align="center",opts="{imageopts}"]
 Submitting an action for execution returns an [code]#event# object. Programmers
 may use these events to explicitly coordinate host and device execution. Host
 code can wait for an event to complete, which will block execution on the host
-until the action(s) represented by the event has completed.  The [code]#event#
+until the action(s) represented by the event have completed.  The [code]#event#
 class is described in greater detail in <<sec:interface.event>>.
 
 Events may also be used to explicitly order the execution of kernels. Host code may