Hints for properties in `Glyphs3-merge` branch

Hey @schriftgestalt!

I am trying the latest version you pushed a couple of weeks ago, and I cannot find the hints you mentioned during our last meeting.

Consider this snippet:

```python
from glyphsLib import GSFont

from dinamo.mastering.constants import TESTS_FONTS_FOLDER

if __name__ == "__main__":
gs_font = GSFont("font.glyphs")
for glyph in gs_font.glyphs:
print(glyph)

```

The language server considers `gs_font.glyphs` as `Any` (default for an attribute without hints)

Instead if I annotate explicitly the property in `classes.py`

```python
glyphs: list[GSGlyph] = property(
lambda self: FontGlyphsProxy(self),
lambda self, value: FontGlyphsProxy(self).setter(value),
)
```

The language server is able to pick up the right class definition.

Start in classes.py, focusing on the GSFont.glyphs property and its FontGlyphsProxy and GSGlyph types. Compare the current declaration with the explicit annotation shown in the issue, then check the example's gs_font.glyphs expression in a Python language server. Done means the property resolves to the appropriate typed class instead of Any.

Written by the indexing model from the issue text.