Remove leftover function binding usages

src/newsreader/js/components/Messages.js

@@ -3,9 +3,7 @@ import React from 'react';
 class Messages extends React.Component {
   state = { messages: this.props.messages };
 
-  close = ::this.close;
-
-  close(index) {
+  close = (index) => {
     const newMessages = this.state.messages.filter((message, currentIndex) => {
       return currentIndex != index;
     });

src/newsreader/js/pages/homepage/components/PostModal.js

@@ -7,7 +7,6 @@ import { SAVED_TYPE, SUBREDDIT } from '../constants.js';
 import { formatDatetime } from '../../../utils.js';
 
 class PostModal extends React.Component {
-  modalListener = ::this.modalListener;
   readTimer = null;
 
   componentDidMount() {
@@ -32,7 +31,7 @@ class PostModal extends React.Component {
     window.removeEventListener('click', this.modalListener);
   }
 
-  modalListener(e) {
+  modalListener = (e) => {
     const targetClassName = e.target.className;
 
     if (this.props.post && targetClassName == 'modal post-modal') {