fix: replace history in 'CommentScrollArrow' (vas3k#1002)

Assigning the value behaves as a 'location.push' and adds a new item
into the 'history' which makes it harded for users to jump to the
previous **page** i.e. feed.

Replacing on the other hand, allows to go to the previous page with a
single "go back".

Author: Nick Gashkov

frontend/static/js/components/CommentScrollArrow.vue

@@ -57,7 +57,7 @@ export default {
             window.addEventListener("scroll", onScroll);
             onScroll();
 
-            document.location.hash = `#${el.id}`;
+            document.location.replace(`#${el.id}`);
         },
         scrollExtreme(direction) {
             if (direction === "Down") {