fix Handle draft chapters (#59)

* Update depedencies

there seems to have been a change in the toml dependency that breaks the
current code.

* Fix handling of draft chapters

otherwise we will not render things that are below daft chapters.

---------

Co-authored-by: Dylan Owen <[email protected]>

src/preprocessor.rs

@@ -79,7 +79,7 @@ impl<R: GraphvizRenderer> Graphviz<R> {
         for item in mem::take(items) {
             item_futures.push(async {
                 match item {
-                    BookItem::Chapter(chapter) if chapter.path.is_some() => {
+                    BookItem::Chapter(chapter) => {
                         self.process_chapter(chapter).await.map(BookItem::Chapter)
                     }
                     item => {
@@ -103,6 +103,10 @@ impl<R: GraphvizRenderer> Graphviz<R> {
         // make sure to process our chapter sub-items
         self.process_sub_items(&mut chapter.sub_items).await?;
 
+        if chapter.path.is_none() {
+            return Ok(chapter);
+        }
+
         // assume we've already filtered out all the draft chapters
         let mut chapter_path = self.src_dir.join(chapter.path.as_ref().unwrap());
         // remove the chapter filename