remove void keyword from sidebar TOC script

Author: dependabot[bot]

package-lock.json

@@ -51,7 +51,7 @@
     "gulp-uglify": "~3.0",
     "gulp-vinyl-zip": "~2.2",
     "handlebars": "~4.7",
-    "highlight.js": "9.18.3",
+    "highlight.js": "10.4.1",
     "js-yaml": "~3.13",
     "merge-stream": "~2.0",
     "postcss-calc": "~7.0",