Add comment with link to issue and open tags

Author: Brian Campbell

tests/rustdoc/extern/pub-extern-crate-150176.rs

@@ -1,5 +1,9 @@
 //@ aux-build:pub-extern-crate.rs
 
+// A refactor had left us missing the closing tags,
+// ensure that they are present.
+// https://github.com/rust-lang/rust/issues/150176
+
 //@ has pub_extern_crate_150176/index.html
-//@ hasraw - 'pub extern crate inner;</code></dt>'
+//@ hasraw - '<dt><code>pub extern crate inner;</code></dt>'
 pub extern crate inner;