Fix sp_BlitzLock qn column to restore 0-based numbering

The qn column was changed from ROW_NUMBER() - 1 (0-based) to
ROW_NUMBER() (1-based), but downstream code still expects 0-based
values. This caused parallel deadlocks to silently drop the second
query (d.qn < 2 only keeps 1 row instead of 2) and made the
WHEN d.qn = 0 labeling branch dead code.

Fixes issue identified by Copilot in PR #3885.

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

Author: BrentOzar

sp_BlitzLock.sql

@@ -3618,7 +3618,7 @@ BEGIN
                     en =
                         DENSE_RANK() OVER (ORDER BY dp.event_date),
                     qn =
-                        ROW_NUMBER() OVER (PARTITION BY dp.event_date ORDER BY dp.event_date),
+                        ROW_NUMBER() OVER (PARTITION BY dp.event_date ORDER BY dp.event_date) - 1,
                     dn =
                         ROW_NUMBER() OVER (PARTITION BY dp.event_date, dp.id ORDER BY dp.event_date),
                     dp.is_victim,
@@ -3703,7 +3703,7 @@ BEGIN
                     en =
                         DENSE_RANK() OVER (ORDER BY dp.event_date),
                     qn =
-                        ROW_NUMBER() OVER (PARTITION BY dp.event_date ORDER BY dp.event_date),
+                        ROW_NUMBER() OVER (PARTITION BY dp.event_date ORDER BY dp.event_date) - 1,
                     dn =
                         ROW_NUMBER() OVER (PARTITION BY dp.event_date, dp.id ORDER BY dp.event_date),
                     is_victim = 1,