Rollup merge of #70270 - GuillaumeGomez:cleanup-e0449, r=Dylan-DPC

Clean up E0449 explanation

r? @Dylan-DPC

Author: Centril

src/librustc_error_codes/error_codes/E0449.md

@@ -1,5 +1,6 @@
-A visibility qualifier was used when it was unnecessary. Erroneous code
-examples:
+A visibility qualifier was used when it was unnecessary.
+
+Erroneous code examples:
 
 ```compile_fail,E0449
 struct Bar;