Fixed formatting of Module doc comments (#5101)

## Description
Closes #5058

swayfmt/src/formatter/mod.rs

@@ -88,23 +88,23 @@ impl Formatter {
 
         self.with_comments_context(src)?;
 
-        let module = parse_file(&self.source_engine, Arc::from(src), path.clone())?.value;
-        module.format(&mut raw_formatted_code, self)?;
+        let annotated_module = parse_file(&self.source_engine, Arc::from(src), path.clone())?;
+        annotated_module.format(&mut raw_formatted_code, self)?;
 
         let mut formatted_code = String::from(&raw_formatted_code);
 
         // Write post-module comments
         write_comments(
             &mut formatted_code,
-            module.span().end()..src.len() + 1,
+            annotated_module.value.span().end()..src.len() + 1,
             self,
         )?;
 
         // Add newline sequences
         handle_newlines(
             &self.source_engine,
             Arc::from(src),
-            &module,
+            &annotated_module.value,
             Arc::from(formatted_code.clone()),
             path,
             &mut formatted_code,

swayfmt/tests/mod.rs

@@ -20,6 +20,20 @@ fn check(unformatted: &str, expected: &str) {
     check_with_formatter(unformatted, expected, &mut formatter);
 }
 
+#[test]
+fn module_doc_comments_persist() {
+    check(
+        r#"
+
+//! this is a module level doc comment
+library;
+        "#,
+        r#"//! this is a module level doc comment
+library;
+"#,
+    )
+}
+
 #[test]
 fn conserve_pub_mod() {
     check(