BUG #17048: about trace_locks parameter problem

The following bug has been logged on the website:

Bug reference:      17048
Logged by:          yanliang lei
Email address:      leiyanliang@highgo.com
PostgreSQL version: 13.3
Operating system:   CentOS7.6
Description:

in the following SQL statement's result ,there is no trace_locks
parameter.
but in the
documents(https://www.postgresql.org/docs/current/runtime-config-developer.html),there
is trace_locks parameter

this problem also applies to PostgreSQL 14 Beta1 Version。

postgres=# select name  from pg_settings where name like '%lock%';
              name              
--------------------------------
 block_size
 deadlock_timeout
 lock_timeout
 log_lock_waits
 max_locks_per_transaction
 max_pred_locks_per_page
 max_pred_locks_per_relation
 max_pred_locks_per_transaction
 wal_block_size
(9 rows)

postgres=# select name from pg_settings where name='trace_locks';
---->>>there is no trace_locks parameter
 name 
------
(0 rows)

postgres=# select version();
                                                 version
                            
---------------------------------------------------------------------------------------------------------
 PostgreSQL 13.3 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5
20150623 (Red Hat 4.8.5-44), 64-bit
(1 row)

postgres=#