docs: fix SnsAction typo for aws-cdk-lib aws_cloudwatch Alarm addAlarmAction (#30867)

### Issue # (if applicable)

N/A

### Reason for this change

Fixing a typo

### Description of changes

Fixing a typo in the docs under aws-cdk-lib aws_cloudwatch Alarm addAlarmAction

### Description of how you validated changes

Spell checker

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: pyepye

packages/aws-cdk-lib/aws-cloudwatch/lib/alarm.ts

@@ -250,7 +250,7 @@ export class Alarm extends AlarmBase {
   /**
    * Trigger this action if the alarm fires
    *
-   * Typically SnsAcion or AutoScalingAction.
+   * Typically SnsAction or AutoScalingAction.
    */
   public addAlarmAction(...actions: IAlarmAction[]) {
     if (this.alarmActionArns === undefined) {