Expose grease pencil `fill_id` and `hide_stroke` attributes to high
level python API. This allows to easily get or set those attributes
using the stroke object itself in scripts or interactive console.
#### Usage:
For the example, let's store a drawing (first frame on first layer of
an active GP object):
`drawing = bpy.context.object.data.layers[0].frames[0].drawing`
Using low level API:
`drawing.attributes['fill_id'].data[0].value = 1`
`drawing.attributes['hide_stroke'].data[0].value = True`
Now also possible directly on stroke object with high level API:
`drawing.strokes[0].fill_id = 1`
`drawing.strokes[0].hide_stroke = True`
Pull Request: https://projects.blender.org/blender/blender/pulls/156246
08f823dcd8