logmon:add static check for logmon exited hook

client/allocrunner/taskrunner/logmon_hook.go

@@ -101,7 +101,7 @@ func (h *logmonHook) Prestart(ctx context.Context,
 	var reattachConfig *plugin.ReattachConfig
 	var err error
 
-	// If the task was restarted then the logmon process is still running and just
+	// If the task was restarted and the logmon process is still running logmon
 	// needs the start RPC called again to open the fifo
 	if !h.exited || h.logmonPluginClient == nil || h.logmonPluginClient.Exited() {
 		reattachConfig, err = reattachConfigFromHookData(req.PreviousState)

client/allocrunner/taskrunner/logmon_hook_test.go

@@ -19,6 +19,7 @@ import (
 
 // Statically assert the logmon hook implements the expected interfaces
 var _ interfaces.TaskPrestartHook = (*logmonHook)(nil)
+var _ interfaces.TaskExitedHook = (*logmonHook)(nil)
 var _ interfaces.TaskStopHook = (*logmonHook)(nil)
 
 // TestTaskRunner_LogmonHook_LoadReattach unit tests loading logmon reattach