[Resources] Add images and ref hyperlinks

https://docs.godotengine.org/en/latest/tutorials/scripting/resources.html

Needs this to be merged first https://github.com/godotengine/godot-docs/pull/6279

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- Images needing replacement: Sprite2D/Texture2D 2 examples

- 5 images on "Godot makes it easy to create custom Resources in the Inspector." to the end of that example. E.g. how to create a resource.

- Ref Hyperlinks needed anywhere "resource(s)" link exists. So, fixing inconsistent styling (the same string sometimes has``, or :ref: , or italic)

- Get the bottom example working. I cannot do `const BotStats = preload("bot_stats.gd")` without compiler going blood-red on me.
Not to mention the `.new()` on the Resource. Admittedly I am a newbie, but I got instancing unique resources by doing
```python
func _int():
setup_local_to_scene()
```
and then on the target script, instead of `.new()`, I used `.duplicate()`
^Not making a PR of this because I don't know if it's the recommended way. Sounds like bloat, especially if something like `.new()` does work!