fix link

Author: merlinorg

docs/2023/puzzles/day20.md

@@ -291,7 +291,7 @@ subgraphs. This terminal conjunction will emit a high pulse when it
 receives a high pulse from each of the subgraphs.
 
 Each subgraph emits a high pulse on a repeating cycle. This reminds us of
-[day 8](5); the soonest point at which all the subgraphs will simultaneously
+[day 8](day05.md); the soonest point at which all the subgraphs will simultaneously
 emit a high pulse will be the
 [least common multiple](https://en.wikipedia.org/wiki/Least_common_multiple)
 of the subgraph cycle times. It is not uncommon for AoC problems to