Statement documentation for `ADMIN SHOW...` is missing docs for `...TELEMETRY`

[dveeden]

Error Report

https://docs.pingcap.com/tidb/stable/sql-statement-admin or other pages documenting the ADMIN statements should include documentation for ADMIN SHOW TELEMETRY.

$ git grep 'ADMIN SHOW TELEMETRY'
telemetry.md:ADMIN SHOW TELEMETRY;
telemetry.md:ADMIN SHOW TELEMETRY;
$ grep -ci telemetry sql-statements/sql-statement-admin*.md
sql-statements/sql-statement-admin-cancel-ddl.md:0
sql-statements/sql-statement-admin-checksum-table.md:0
sql-statements/sql-statement-admin-check-table-index.md:0
sql-statements/sql-statement-admin.md:0
sql-statements/sql-statement-admin-show-ddl.md:0