message: Fix exports_memory example
diff: @@ -29,7 +29,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
  global.get $offset
  global.get $length)
  - (data (global.get $offset) "Hello, World!"))
  + (data (i32.const 42) "Hello, World!"))
  "#,
  )?;
  