Add rustdoc-js test

Finally!

Author: camelid

src/test/rustdoc-js/basic.rs

@@ -1,2 +1,2 @@
-/// Foo
+/// Docs for Foo
 pub struct Foo;

src/test/rustdoc-js/summaries.js

@@ -0,0 +1,7 @@
+const QUERY = 'summaries';
+
+const EXPECTED = {
+    'others': [
+        { 'path': '', 'name': 'summaries', 'desc': 'This <em>summary</em> has a link and <code>code</code>.' },
+    ],
+};

src/test/rustdoc-js/summaries.rs

@@ -0,0 +1,18 @@
+#![crate_type = "lib"]
+#![crate_name = "summaries"]
+
+//! This *summary* has a [link] and `code`.
+//!
+//! This is the second paragraph.
+//!
+//! [link]: https://example.com
+
+/// This `code` will be rendered in a code tag.
+///
+/// This text should not be rendered.
+pub struct Sidebar;
+
+/// ```text
+/// this block should not be rendered
+/// ```
+pub struct Sidebar2;