Add GQLSTATUS code to Neo. code

Author: renetapopova

modules/ROOT/pages/database-internals/concurrent-data-access.adoc

@@ -295,6 +295,8 @@ Since locks are used, deadlocks can happen.
 A deadlock occurs when two transactions are blocked by each other because they are attempting to concurrently modify a node or a relationship that is locked by the other transaction.
 In such a scenario, neither of the transactions will be able to proceed.
 When Neo4j detects a deadlock, the transaction is terminated with the transient error message code `Neo.TransientError.Transaction.DeadlockDetected`.
+From 5.25 onwards, the error also contains the following additional GQLSTATUS code and information along with the Neo4j exception:
+`50N05, error: general processing exception - deadlock detected. Deadlock detected while trying to acquire locks. See log for more details.``
 
 All locks acquired by the transaction are still held but will be released when the transaction finishes.
 Once the locks are released, other transactions that were waiting for locks held by the transaction causing the deadlock can proceed.