Collision shapes behave as if they are bigger than what it should be

[DeeJayLSP]

Describe the bug
CharacterBody2D collisions (I haven't tested other body types) behave like they are somewhat bigger than what shows with Visible Collision Shapes on.

Box2D/Rapier2D

To Reproduce
Steps to reproduce the behavior:

1. Make a 2D platformer like the one above.
2. Move the character to a wall and see the distance between the shapes.

Expected behavior
The same as the Rapier2D example above.

If this is intended at least could be documented

Versions (please complete the following information):

• OS: [Ubuntu 22.04]
• Godot [v4.2 beta5]
• Box2d [v0.9.2]

[Ughuuu]

Interesting. I think this is the polygon skin that box2d has. I have removed it in the past, but forgot in this new impl. I will document it in the readme, and I think I would wait for box2d v3 to appear(as that one doesnt use this polygon skin anymore).

You can view progress state here: erincatto/box2c#44

[Ughuuu]

Added a documentation in the readme:

Hope box2c will fix it by removing polygon skin.