Clarify comment in tablesync.c
Author: Peter Smith
Discussion:
* CATCHUP -> SYNCDONE -> READY.
*
* The catalog pg_subscription_rel is used to keep information about
- * subscribed tables and their state. Some transient state during data
- * synchronization is kept in shared memory. The states SYNCWAIT and
- * CATCHUP only appear in memory.
+ * subscribed tables and their state. The catalog holds all states
+ * except SYNCWAIT and CATCHUP which are only in shared memory.
*
* Example flows look like this:
* - Apply is in front:
