Add note on transactions being stateful

Author: flyingsilverfin

manual/modules/ROOT/pages/queries/transactions.adoc

@@ -7,6 +7,10 @@ TypeDB transactions come in 3 flavors: *read*, *write*, and *schema* transaction
 
 TypeDB transactions provide *ACID guarantees* up to snapshot isolation.
 
+All transactions that can do writes in TypeDB are __stateful__: queries that mutate the schema or data
+have their changes buffered and are accessible to following queries in the transaction. After a commit,
+the changes are merged into the global database state and made accessibly to new transactions.
+
 == Read transactions
 
 Read transactions can execute only read queries, and will error when provided data update queries or schema mutation queries.