fix: Escape characters visible in TOC

closes #1226

shared/utils/getHeadingsForText.js

@@ -1,6 +1,7 @@
 // @flow
 import { filter } from 'lodash';
 import slugify from 'shared/utils/slugify';
+import unescape from 'shared/utils/unescape';
 
 export default function getHeadingsForText(
   text: string
@@ -13,7 +14,7 @@ export default function getHeadingsForText(
     if (!match) continue;
 
     const level = match[1].length;
-    const title = match[2];
+    const title = unescape(match[2]);
 
     let slug = slugify(title);
     const existing = filter(output, { slug });

shared/utils/getHeadingsForText.test.js

@@ -0,0 +1,23 @@
+/* eslint-disable flowtype/require-valid-file-annotation */
+import getHeadingsForText from './getHeadingsForText';
+
+it('should return an array of document headings', () => {
+  const response = getHeadingsForText(`
+# Header
+  
+## Subheading
+`);
+
+  expect(response.length).toBe(2);
+  expect(response[0].level).toBe(1);
+  expect(response[0].title).toBe('Header');
+  expect(response[1].level).toBe(2);
+  expect(response[1].title).toBe('Subheading');
+});
+
+it('should unescape special characters', () => {
+  const response = getHeadingsForText(`# Header <\\>`);
+
+  expect(response.length).toBe(1);
+  expect(response[0].title).toBe('Header <>');
+});