Include trailing newline in pretty print output

src/main.rs

@@ -80,7 +80,7 @@ fn main() -> anyhow::Result<()> {
                 .parse(stream)
                 .map_err(|e| anyhow!("{e:?}"))?;
 
-            println!("{}", pretty::pretty_to_string(program, 100));
+            print!("{}", pretty::pretty_to_string(program, 100));
         }
 
         Command::Desugar {

src/pretty.rs

@@ -21,5 +21,7 @@ pub fn pretty_to_string<P: Pretty<'static, RcAllocator>>(p: P, width: usize) ->
     p.pretty(&RcAllocator)
         .render(width, &mut out)
         .expect("p could not be rendered");
-    String::from_utf8(out).expect("p created non-utf8 string")
+    let mut s = String::from_utf8(out).expect("p created non-utf8 string");
+    s.push('\n');
+    s
 }