fix #411 (#412)

blog/content/second-edition/posts/03-vga-text-buffer/index.md

@@ -576,7 +576,7 @@ pub fn print(args: fmt::Arguments) {
 The `print` function locks our static `WRITER` and calls the `write_fmt` method on it. This method is from the `Write` trait, we need to import that trait. The additional `unwrap()` at the end panics if printing isn't successful. But since we always return `Ok` in `write_str`, that should not happen.
 
 ### Hello World using `println`
-To use `println` in `lib.rs`, we need to import the macros of the VGA buffer module first. Therefore we add a `#[macro_use]` attribute to the module declaration:
+To use `println` in `main.rs`, we need to import the macros of the VGA buffer module first. Therefore we add a `#[macro_use]` attribute to the module declaration:
 
 ```rust
 // in src/main.rs