Handle HTML inside headings for ToC

Previously, the HTML tag would break the `content` match,
resulting in an incorrect navigation item. By excluding the
opening tag from the link pattern, inlide code can now be
parsed correctly inside of headings.

src/blocks/utilities/tocReader.js

@@ -3,15 +3,15 @@
  */
 export class TocReader {
   static matcher =
-    /<h(?<level>[2-4])><a.*id="(?<href>.*?)".*>(?<content>.*?)<\/a><\/h\1>/g;
+    /<h(?<level>[2-4])><a.*id="(?<href>.*?)"[^<]*>(?<content>.*?)<\/a><\/h\1>/g;
 
   static readToC = html => {
     if (!html) return undefined;
     const headings = [...html.matchAll(TocReader.matcher)].map(({ groups }) => {
       return {
         level: Number.parseInt(groups.level, 10),
         href: groups.href,
-        content: groups.content.trim(),
+        content: groups.content.replace(/<[^>]*>/g, '').trim(),
       };
     });
     if (headings.length === 0) return undefined;