Rollup merge of rust-lang#70355 - GuillaumeGomez:cleanup-e0454, r=Dylan-DPC

Clean up E0454

r? @Dylan-DPC

Author: Centril

src/librustc_error_codes/error_codes/E0454.md

@@ -1,4 +1,6 @@
-A link name was given with an empty name. Erroneous code example:
+A link name was given with an empty name.
+
+Erroneous code example:
 
 ```compile_fail,E0454
 #[link(name = "")] extern {}