replication instrumentation for the Performance Schema has been added into 10.6.0 and needs documentation.

Changes to the merge from 5.7 include:

1. MDEV-16437: merge 5.7 P_S replication instrumentation and tables
Merge 'replication_applier_status' table.
This table captures SQL_THREAD status.
2. MDEV-16437: merge 5.7 P_S replication instrumentation and tables
Merge 'replication_applier_configuration' table.
This table captures SQL_THREAD configuration parameters.
3. MDEV-16437: merge 5.7 P_S replication instrumentation and tables
Merge 'replication_applier_status_by_coordinator' table.
This table captures SQL_THREAD status in case of both single threaded and
multi threaded slave configuration. When multi_source replication is enabled
this table will display each source specific SQL_THREAD status.
Added new columns for:
-> LAST_SEEN_TRANSACTION
-> LAST_TRANS_RETRY_COUNT
4. MDEV-16437: merge 5.7 P_S replication instrumentation and tables
Merge 'replication_connection_configuration' table.
Replaced following column:
-> AUTO_POSITION with USING_GTID
Added new columns for:
-> IGNORE_SERVER_IDS
-> DO_DOMAIN_IDS
-> IGNORE_SERVER_IDS
Removed following columns as they are not part of mariadb replication
connection configuration:
-> NETWORK_INTERFACE
-> TLS_VERSION
@sql/mysqld.cc
Changed "master-retry-count" default value to 100000.