Fix clippy doc comment lint

Author: jtgeibel

src/version/cache.rs

@@ -19,7 +19,8 @@ use super::version_and_crate;
 /// This information can be obtained direclty from the index.
 ///
 /// In addition to returning cached data from the index, this returns
-/// fields for id, version_id, and downloads (which appears to always be 0)
+/// fields for `id`, `version_id`, and `downloads` (which appears to always
+/// be 0)
 pub fn dependencies(req: &mut Request) -> CargoResult<Response> {
     let (version, _) = version_and_crate(req)?;
     let conn = req.db_conn()?;