restore comment

Author: Oneirical

tests/run-make/external-crate-panic-handle-no-lint/rmake.rs

@@ -1,6 +1,7 @@
 // Defining a crate that provides panic handling as an external crate
-// could uselessly trigger the "unused external crate" lint. This test
-// creates this situation and checks that the lint is not triggered.
+// could uselessly trigger the "unused external crate" lint. A fix was
+// created, and this test checks that the fix did not accidentally break
+// compiler functionality.
 // See https://github.com/rust-lang/rust/issues/53964
 
 use run_make_support::{rustc, tmp_dir};