Rewording to make spell checker happy

Author: Brian-Campuzano

Svc/Ccsds/CfdpManager/docs/sdd.md

@@ -306,7 +306,7 @@ sequenceDiagram
 - NAK processing during file data transmission:
   - NAKs received during file data transmission (before EOF is sent) are processed immediately
   - Requested gap segments are queued and retransmitted with priority over new file data
-  - This allows gaps to be filled proactively as they are detected, rather than waiting for EOF acknowledgment
+  - This allows gaps to be filled immediately upon detection, rather than waiting for EOF acknowledgment
 - FIN PDU from receiver confirms final delivery status
 - Timers ensure protocol progress and detect failures
   - Spacecraft ACK timer: Armed when EOF is sent with duration `ChannelConfig.ack_timer`, cancelled when ACK(EOF) or FIN is received. If the timer expires before receiving acknowledgment, the spacecraft retransmits EOF and rearms the timer. After `ChannelConfig.ack_limit` retries without acknowledgment, the transaction is abandoned with status `ACK_LIMIT_NO_EOF`