Add editorconfig to trim trailing whitespace

.editorconfig

@@ -23,3 +23,5 @@ indent_size = 2
 # Tab indentation (no size specified)
 [Makefile]
 indent_style = tab
+
+trim_trailing_whitespace = true

app/src/static/preload.js

@@ -17,7 +17,7 @@ document.addEventListener('DOMContentLoaded', () => {
     window.addEventListener('contextmenu', event => {
         event.preventDefault();
         let targetElement = event.srcElement;
-        
+
         // the clicked element is the deepest in the DOM, and may not be the <a> bearing the href
         // for example, <a href="..."><span>Google</span></a>
         while (!targetElement.href && targetElement.parentElement) {