Update src/part2/serial-link.md

Co-authored-by: Antonio Vivace <avivace4@gmail.com>

Author: quinnyo

src/part2/serial-link.md

@@ -251,7 +251,7 @@ The errors that we're concerned with are data replication errors -- any case whe
 <!-- Link/checksum -->
 The first step is detection.
 The receiver needs to test the integrity of every incoming data packet, before doing anything else with it.
-We'll use a checksum for this:
+We'll use a [checksumming](https://en.wikipedia.org/wiki/Checksum) mechanism for this:
 - The sender calculates a checksum of the outgoing packet and the result is transmitted as part of the packet transfer.
 - The receiver performs the same calculation and compares the result with the value from the sender.
 - If the values match, the packet is intact.