Auto merge of #2564 - Turbo87:prism, r=locks

modifiers/highlight-syntax: Disable aggressive whitespace stripping

see https://prismjs.com/plugins/normalize-whitespace/

Resolves #2498

r? @locks

Author: bors

app/modifiers/highlight-syntax.js

@@ -1,6 +1,12 @@
 /* global Prism */
 import { modifier } from 'ember-modifier';
 
+Prism.plugins.NormalizeWhitespace.setDefaults({
+  'left-trim': false,
+  'right-trim': true,
+  'remove-initial-line-feed': true,
+});
+
 export default modifier((element, _, { selector }) => {
   let elements = selector ? element.querySelectorAll(selector) : [element];