Fix slow giscus.app page load times

**Your Godot version:**

Latest/all

**Issue description:**

Looks like those pages that do not have comments have very slow page load speed because the page is loading slow Giscus app pages that either return 404 like: https://giscus.app/api/discussions?repo=godotengine%2Fgodot-docs-user-notes&term=classes%2Fclass_material&category=User-contributed+notes&number=0&strict=true&last=15 or take a very long time. You can inspect this with Chrome dev tools but this page takes 8 seconds to load on a fast connection. Perhaps avoid waiting on Giscus URLs before rendering the entirety of the page.

**URL to the documentation page (if already existing):**

https://docs.godotengine.org/en/stable/classes/class_material.html#class-material-method-inspect-native-shader-code