Set needs_indirect_abi for Array

Otherwise:

    warning: `extern` fn uses type `[u8; 3]`, which is not FFI-safe
     --> src/main.rs:8:21
      |
    8 |         fn arr() -> [u8; 3];
      |                     ^^^^^^^ not FFI-safe
      |
      = note: `#[warn(improper_ctypes_definitions)]` on by default
      = help: consider passing a pointer to the array
      = note: passing raw arrays by value is not FFI-safe

syntax/types.rs

@@ -254,7 +254,7 @@ impl<'a> Types<'a> {
                     Atom::from(&ident.rust) == Some(RustString)
                 }
             }
-            Type::RustVec(_) => true,
+            Type::RustVec(_) | Type::Array(_) => true,
             _ => false,
         }
     }