Update rpc-transaction-history.md

docs/src/implemented-proposals/rpc-transaction-history.md

@@ -42,7 +42,7 @@ different tables for quick searching.
 
 New data may be copied into the instance at anytime without affecting the
 existing data, and all data is immutable. Generally the expectation is that new
-data will be uploaded once an current epoch completes but there is no limitation
+data will be uploaded once a current epoch completes but there is no limitation
 on the frequency of data dumps.
 
 Cleanup of old data is automatic by configuring the data retention policy of the