# Remove trailing whitespace from output lines

```ocaml
# let x = 13;;
val x : int = 13  
```

```sh
$ echo "bob  "
bob  
```

Also, it should be valid to terminate phrases that end with `;;` but have
trailing whitespace:

```ocaml
# let terminated_with_space = 42;; 
val terminated_with_space : int = 42
# let terminated_with_tab = 42;;	
val terminated_with_tab : int = 42
```
