Fix use of the move command in the Windows shell

`move` work both in `cmd` and in Powershell. `mv` works only in Powershell and the book says nothing about which shell is recommended so this could confuse beginners.

Closes #33219.

src/doc/book/getting-started.md

@@ -412,7 +412,7 @@ enter the following commands:
 
 ```bash
 $ mkdir src
-$ mv main.rs src/main.rs
+$ mv main.rs src/main.rs # or 'move main.rs src/main.rs' on Windows
 $ rm main  # or 'del main.exe' on Windows
 ```