Update description of alerts.json (Azure#22841)

* Update alerts.json

* Update alerts.json

Author: msyyc

specification/security/resource-manager/Microsoft.Security/stable/2022-01-01/alerts.json

@@ -971,7 +971,7 @@
         "productName": {
           "readOnly": true,
           "type": "string",
-          "description": "The name of the product which published this alert (Azure Security Center, Azure ATP, Microsoft Defender ATP, O365 ATP, MCAS, and so on)."
+          "description": "The name of the product which published this alert (Microsoft Sentinel, Microsoft Defender for Identity, Microsoft Defender for Endpoint, Microsoft Defender for Office, Microsoft Defender for Cloud Apps, and so on)."
         },
         "processingEndTimeUtc": {
           "readOnly": true,