syn: Fix `Hash::new_from_array` warning in non-bpf targets (#2693)

lang/syn/src/hash.rs

@@ -78,6 +78,7 @@ impl Hash {
         Hash(<[u8; HASH_BYTES]>::try_from(hash_slice).unwrap())
     }
 
+    #[cfg(target_arch = "bpf")]
     pub const fn new_from_array(hash_array: [u8; HASH_BYTES]) -> Self {
         Self(hash_array)
     }
@@ -102,7 +103,7 @@ pub fn hashv(vals: &[&[u8]]) -> Hash {
     {
         extern "C" {
             fn sol_sha256(vals: *const u8, val_len: u64, hash_result: *mut u8) -> u64;
-        };
+        }
         let mut hash_result = [0; HASH_BYTES];
         unsafe {
             sol_sha256(