Fix definition selector for functions

Previosuly, we always used the selector ".docblock.type-decl" to select
the definition for an item.  But this did not work for functions.
Therefore we change the selector to "pre.fn" for functions.

CHANGELOG.md

@@ -9,6 +9,7 @@ SPDX-License-Identifier: MIT
   environment variable `RUST_LOG=info`.
   - Add `env_logger` dependency in version 0.7.1.
   - Add `log` dependency in version 0.4.11.
+- Show the definition for global functions.
 
 # v0.1.1 (2020-07-24)
 

src/parser.rs

@@ -79,7 +79,12 @@ fn select_first(
 
 pub fn parse_item_doc(item: &doc::Item) -> anyhow::Result<doc::Doc> {
     let document = parse_file(&item.path)?;
-    let definition = select_first(&document, ".docblock.type-decl")?;
+    let definition_selector = if item.ty == doc::ItemType::Function {
+        "pre.fn"
+    } else {
+        ".docblock.type-decl"
+    };
+    let definition = select_first(&document, definition_selector)?;
     let description = select_first(&document, "#main > .docblock:not(.type-decl)")?;
 
     let mut doc = doc::Doc::new(item.name.clone(), item.ty);