Force clippy to be happy

src/day06.rs

@@ -25,6 +25,7 @@ impl Day06 {
     fn do_magic(&self, days: u64) -> u64 {
         (0..days).fold(self.0, Self::foo).iter().sum()
     }
+    #[allow(clippy::many_single_char_names)]
     fn foo([a, b, c, d, e, f, g, h, i]: [u64; 9], _: u64) -> [u64; 9] {
         [b, c, d, e, f, g, h + a, i, a]
     }