Add reference table linnk

Signed-off-by: Matt Lord <[email protected]>

changelog/21.0/21.0.0/summary.md

@@ -226,8 +226,8 @@ which takes a string where the valid values today are `LEAVE` (leave the `auto_i
 `--remove-sharded-auto-increment[=true]` behavior in v21 is equal to the new `--sharded-auto-increment-handling=remove` behavior in v21+. To use the new support for automatically replacing those
 MySQL `auto_increment` clauses with Vitess Sequences, you would utilize these two
 [`MoveTables create` flags](https://vitess.io/docs/21.0/reference/programs/vtctldclient/vtctldclient_movetables/vtctldclient_movetables_create/): `--sharded-auto-increment-handling=replace --global-keyspace=foo`
-where `foo` is an unsharded keyspace that can be used for sequences, reference tables, etc. That keyspace is where the sequence tables will be created as needed as part of the replacement work.
-Then, when switching the application traffic to the target keyspace you would specify the
+where `foo` is an unsharded keyspace that can be used for sequences, [reference tables](https://vitess.io/docs/21.0/reference/vreplication/reference_tables/), and other "global" resources. That keyspace is
+where the sequence tables will be created as needed as part of the replacement work. Then, when switching the application traffic to the target keyspace you would specify the
 [`--initialize-target-sequences` flag for the `MoveTables switchtraffic` command](https://vitess.io/docs/reference/programs/vtctldclient/vtctldclient_movetables/vtctldclient_movetables_switchtraffic/).
 It's at this point where the sequence tables will be created, if needed, and the starting value used will be initialized based on the current maximum value used for the table in the unsharded source
 keyspace. This allows us to replace the MySQL feature with the equivalent Vitess one in a way that is entirely transparent to the application and its users — they can continue to elide values for the