Fix XE event name in Azure help message: database_xml_deadlock_report

Azure SQL DB uses database_xml_deadlock_report, not xml_deadlock_report.
Tested end-to-end: created the suggested XE session on Azure SQL DB,
ran sp_BlitzLock successfully against it, and tore it back down.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: BrentOzar

sp_BlitzLock.sql

@@ -580,7 +580,7 @@ To use sp_BlitzLock in Azure SQL DB, you have two options:
 1. Create a database-scoped deadlock XE session, e.g.:
 
    CREATE EVENT SESSION [deadlocks] ON DATABASE
-   ADD EVENT sqlserver.xml_deadlock_report
+   ADD EVENT sqlserver.database_xml_deadlock_report
    ADD TARGET package0.ring_buffer;
    ALTER EVENT SESSION [deadlocks] ON DATABASE STATE = START;