Use iconNode instead of pseudoclass for icon

assets/javascripts/discourse/widgets/remove-vote.js.es6

@@ -1,4 +1,5 @@
 import { createWidget } from "discourse/widgets/widget";
+import { iconNode } from "discourse-common/lib/icon-library";
 
 export default createWidget("remove-vote", {
   tagName: "div.remove-vote",
@@ -8,7 +9,7 @@ export default createWidget("remove-vote", {
   },
 
   html() {
-    return ["Remove vote"];
+    return [iconNode("times"), "Remove vote"];
   },
 
   click() {

assets/stylesheets/common/feature-voting.scss

@@ -35,9 +35,7 @@
     background-color: $primary-low;
   }
 }
-.vote-option.remove-vote:before {
-  content: $fa-var-close;
-  font-family: FontAwesome;
+.vote-option.remove-vote .d-icon {
   margin-right: 6px;
   color: $danger;
 }