Add tests for basic intra-doc links

src/test/rustdoc/intra-doc-crate/auxiliary/intra-doc-basic.rs

@@ -0,0 +1,5 @@
+#![crate_name = "a"]
+pub struct Foo;
+
+/// Link to [Foo]
+pub struct Bar;

src/test/rustdoc/intra-doc-crate/basic.rs

@@ -0,0 +1,6 @@
+// aux-build:intra-doc-basic.rs
+// build-aux-docs
+extern crate a;
+
+// @has 'basic/struct.Bar.html' '//a[@href="../a/struct.Foo.html"]' 'Foo'
+pub use a::Bar;