fix(zkvms/zkwasm): Explicit type in argument

In certain cases, we would get errors that the "x" type cannot be
inferred.

Author: Syndamia

zkvms/zkwasm/host/src/main.rs

@@ -28,7 +28,7 @@ macro_rules! build_input {
             }
             let bytes = all
                 .into_iter()
-                .map(|x| x.to_be_bytes())
+                .map(|x: u64| x.to_be_bytes())
                 .flatten()
                 .collect::<Vec<u8>>();
             std::fs::write($path, bytes);