windows-restart: Update documentation for restart_check_command (#11507)

Closes #11467

provisioner/windows-restart/provisioner.go

@@ -40,8 +40,9 @@ type Config struct {
 	// The command used to restart the guest machine
 	RestartCommand string `mapstructure:"restart_command"`
 
-	// The command used to check if the guest machine has restarted
-	// The output of this command will be displayed to the user
+	// The command to run after executing `restart_command` to check if the guest machine has restarted.
+	// This command will retry until the connection to the guest machine has been restored or `restart_timeout` has exceeded.
+	// The output of this command will be displayed to the user.
 	RestartCheckCommand string `mapstructure:"restart_check_command"`
 
 	// The timeout for waiting for the machine to restart

website/content/docs/provisioners/windows-restart.mdx

@@ -78,8 +78,9 @@ Optional parameters:
 - `restart_command` (string) - The command to execute to initiate the
   restart. By default this is `shutdown /r /f /t 0 /c "packer restart"`.
 
-- `restart_check_command` (string) - A command to execute to check if the
-  restart succeeded. This will be done in a loop. Example usage:
+- `restart_check_command` (string) - The command to run after executing `restart_command`
+  to check if the guest machine has restarted. This command will retry until the connection
+  to the guest machine has been restored or `restart_timeout` has exceeded.
 
 <Tabs>
 <Tab heading="HCL2">