Fix 2023 day 20 for API.

src/holt59/aoc/2023/day20.py

@@ -1,4 +1,3 @@
-import sys
 from collections import defaultdict
 from math import lcm
 from typing import Any, Iterator, Literal, TypeAlias
@@ -67,7 +66,7 @@ class Solver(BaseSolver):
     def solve(self, input: str) -> Iterator[Any]:
         self._modules = {}
 
-        lines = sys.stdin.read().splitlines()
+        lines = input.splitlines()
 
         for line in lines:
             name, outputs_s = line.split(" -> ")