Fix dead link (#79)

Author: typed-sigterm

docs/05-themes-components/28-global-icon-changes.md

@@ -108,7 +108,7 @@ const REPLACEMENTS = {
 };
 ```
 
-Ref: [discourse/icon-library.js at main · discourse/discourse (github.com)](https://github.com/discourse/discourse/blob/main/app/assets/javascripts/discourse/app/lib/icon-library.js)
+Ref: [discourse/icon-library.js at main · discourse/discourse (github.com)](https://github.com/discourse/discourse/blob/main/frontend/discourse/app/lib/icon-library.js)
 [/details]
 
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