Load module documentation

Previously, we could only print documentation for the items listed in
all.html.  With this patch, we also load the documentation for modules
(including crates) from the <module>/index.html file.  Note that items
are preferred over modules if there is documentation for both (e. g.
std::u8 is both a module and a primitive).

src/doc.rs

@@ -34,6 +34,18 @@ impl Crate {
         parser::find_item(self.path.join("all.html"), &name)
             .map(|o| o.map(|s| Item::new(name, self.path.join(path::PathBuf::from(s)))))
     }
+
+    pub fn find_module(&self, item: &[&str]) -> Option<Item> {
+        let path = self
+            .path
+            .join(path::PathBuf::from(item.join("/")))
+            .join("index.html");
+        if path.is_file() {
+            Some(Item::new(item.join("::"), path))
+        } else {
+            None
+        }
+    }
 }
 
 impl Item {

src/main.rs

@@ -82,6 +82,7 @@ fn find_doc(sources: &[Box<dyn source::Source>], keyword: &str) -> anyhow::Resul
     let crate_ = find_crate(sources, parts[0])?;
     let item = crate_
         .find_item(&parts[1..])?
+        .or_else(|| crate_.find_module(&parts[1..]))
         .with_context(|| format!("Could not find the item {}", keyword))?;
     item.load_doc()
 }
@@ -100,6 +101,8 @@ fn find_crate(sources: &[Box<dyn source::Source>], name: &str) -> anyhow::Result
 mod tests {
     use std::path;
 
+    use crate::source;
+
     pub fn ensure_docs() -> path::PathBuf {
         let doc = path::PathBuf::from("./target/doc");
         assert!(
@@ -108,4 +111,16 @@ mod tests {
         );
         doc
     }
+
+    #[test]
+    fn test_find_doc() {
+        let path = ensure_docs();
+        let sources = vec![source::get_source(path).unwrap()];
+
+        super::find_doc(&sources, "kuchiki").unwrap();
+        super::find_doc(&sources, "kuchiki::NodeRef").unwrap();
+        super::find_doc(&sources, "kuchiki::traits").unwrap();
+        super::find_doc(&sources, "kachiki").unwrap_err();
+        super::find_doc(&sources, "kuchiki::NodeDataRef::as_node").unwrap_err();
+    }
 }