Create advent prelude and cleanup lint by using it.

src/lib.rs

@@ -0,0 +1,13 @@
+pub mod prelude {
+    pub use std::{
+        convert::Infallible,
+        fmt::{Debug, Error, Formatter},
+        io::Read,
+        num::ParseIntError,
+        ops::{Index, IndexMut},
+        str::FromStr,
+    };
+
+    pub use anyhow::Result;
+    pub use thiserror::Error;
+}