Fix linting on frontend TS

Add return type (void) to replaceIcons function

src/assets/ts/featherIcons.ts

@@ -2,7 +2,7 @@ import feather from "feather-icons";
 
 let alreadyReplaced = false;
 
-export function replaceIcons(once: boolean = true) {
+export function replaceIcons(once: boolean = true): void {
     if (!once || !alreadyReplaced) {
         alreadyReplaced = true;
         feather.replace();