Document the newly added wait events added by commit 216a784829.

Author: Shinoda, Noriyoshi
Reviewed-by: Hou Zhijie
Discussion: https://postgr.es/m/DM4PR84MB173460530245F56364E1DAF7EEFE9@DM4PR84MB1734.NAMPRD84.PROD.OUTLOOK.COM

doc/src/sgml/monitoring.sgml

@@ -1131,6 +1131,11 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
       <entry><literal>LogicalLauncherMain</literal></entry>
       <entry>Waiting in main loop of logical replication launcher process.</entry>
      </row>
+     <row>
+      <entry><literal>LogicalParallelApplyMain</literal></entry>
+      <entry>Waiting in main loop of logical replication parallel apply
+       process.</entry>
+     </row>
      <row>
       <entry><literal>RecoveryWalStream</literal></entry>
       <entry>Waiting in main loop of startup process for WAL to arrive, during
@@ -1727,6 +1732,11 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
       <entry>Waiting for other Parallel Hash participants to finish inserting
        tuples into new buckets.</entry>
      </row>
+     <row>
+      <entry><literal>LogicalParallelApplyStateChange</literal></entry>
+      <entry>Waiting for a logical replication parallel apply process to change
+       state.</entry>
+     </row>
      <row>
       <entry><literal>LogicalSyncData</literal></entry>
       <entry>Waiting for a logical replication remote server to send data for