* Clip groups: Release Clipping Mask takes the layers above; merges keep clipping; Delete Hidden settles
From the layers audit (L2, silently wrong results):
- Release Clipping Mask on a clipped layer also releases the clipped layers above it, as
Adobe documents ("removes the selected layer and any layers above it from the clipping
mask"). Before, they stayed clipped to the released layer.
- Merge Down of two clipped layers, and Merge Layers of clipped layers of one chain, give a
layer still clipped to their base (it was always unclipped). Merge Down's result also keeps
the lower layer's colour label and link; Merge Layers' keeps the top layer's label.
- Delete Hidden Layers releases the layers clipped to a deleted hidden base (clip_group rule
3, as single Delete already does), instead of leaving them clipped to the layer below.
* Merge Layers keeps the result clipped only when the clipped layers share one clip chain
* fmt
