mypy thinks Image and Tilemap have no methods
When running `mypy --strict` on my pyxel project, I am getting the following error messages:

```
ichor\world\level.py:89: error: "Tilemap" has no attribute "set"  [attr-defined]   
ichor\world\world.py:26: error: "Tilemap" has no attribute "image"  [attr-defined] 
ichor\game.py:18: error: "Image" has no attribute "load"  [attr-defined]
ichor\game.py:19: error: "Image" has no attribute "load"  [attr-defined]
ichor\game.py:20: error: "Image" has no attribute "load"  [attr-defined]
```

Upon inspection, it looks like there is a part of `__init__.pyi` that defines **Image** and **Tilemap** as a sort of forward declaration:

```python
# Graphics
class Image: ...
class Tilemap: ...
```

If I delete the forward declarations and move the correct definitions from later in the file to where these forward declarations were, `mypy` can now find the methods on the class just fine.

I am running Python 3.11.5 with the following `requirements.txt`:
```
mypy==1.5.1
mypy-extensions==1.0.0
pyxel==1.9.18
typing_extensions==4.7.1
```