Fix definition for methods in documentation parser

This patch changes the documentation parser for methods to use the first
code child of the subheading as the definition instead of the first
child.  This fixes a problems when there is additional information in
the subheading, for example about the relevant traits.

CHANGELOG.md

@@ -9,6 +9,8 @@ SPDX-License-Identifier: MIT
 
 - Use `rustc --print sysroot` to determine the Rust installation directory
   instead of always using `/usr`.
+- Improve the documentation parser:
+  - Fix the definition of methods to only contain the actual definition.
 
 ## v0.1.2 (2020-07-25)
 

src/parser.rs

@@ -82,6 +82,15 @@ fn select(
         .with_context(|| format!("Could not apply selector {}", selector))
 }
 
+fn it_select<I: kuchiki::iter::NodeIterator>(
+    iter: I,
+    selector: &str,
+) -> anyhow::Result<kuchiki::iter::Select<kuchiki::iter::Elements<I>>> {
+    iter.select(selector)
+        .ok()
+        .with_context(|| format!("Could not apply selector {}", selector))
+}
+
 fn select_first(
     element: &kuchiki::NodeRef,
     selector: &str,
@@ -89,6 +98,13 @@ fn select_first(
     select(element, selector).map(|mut i| i.next())
 }
 
+fn it_select_first<I: kuchiki::iter::NodeIterator>(
+    iter: I,
+    selector: &str,
+) -> anyhow::Result<Option<kuchiki::NodeDataRef<kuchiki::ElementData>>> {
+    it_select(iter, selector).map(|mut i| i.next())
+}
+
 pub fn find_examples(s: &str) -> anyhow::Result<Vec<doc::Example>> {
     let element = parse_string(s)?;
     let examples = select(&element, ".rust-example-rendered")?;
@@ -368,7 +384,9 @@ fn get_method_group(
         if is_element(&element, &heading_type) && has_class(&element, "method") {
             methods.push(&mut name, &mut definition, None)?;
             name = get_id_part(&element, 1);
-            definition = element.first_child().map(|n| get_html(&n)).transpose()?;
+            definition = it_select_first(element.children(), "code")?
+                .map(|n| get_html(n.as_node()))
+                .transpose()?;
         } else if is_element(&element, &local_name!("div")) && has_class(&element, "docblock") {
             methods.push(&mut name, &mut definition, Some(&element))?;
         }