Use asserts in array

codegen/array/snippets/array_get

@@ -1,6 +1,4 @@
-  if (!array || index >= array->count) {{
-    return NULL;
-  }}
+  assert(array != NULL & index < array->count);
 
   u8 *ptr = (u8 *)(array->items) + (array->item_size * index);
   return ({T} *)ptr;