fix: faces a sheet fold moves keep their names (#535) (#585)

Faces that a sheet fold or unfold moves keep their names: points on a moved panel are taken back through the panel they lie on to where the sheet held them before the feature, and named from the faces there. Un-ignores the #535 regression test. Fixes #535.

Co-authored-by: jonaswre <[email protected]>

crates/doc/src/eval.rs

@@ -364,7 +364,8 @@ impl ModelState {
     fn stamp(&mut self, before: &Arc<ModelState>, f: &Feature, key: u64, mats: Vec<Mat>) {
         let feature = f.id;
         let depth = before.bodies.iter().filter_map(|b| b.names.origin.as_ref().map(|o| o.depth)).max().unwrap_or(0) + 1;
-        let origin = Arc::new(crate::naming::NamingOrigin { feature: f.clone(), before: before.clone(), depth, mats });
+        let sheets = if f.kind.is_sheet() { self.sheets.clone() } else { Vec::new() };
+        let origin = Arc::new(crate::naming::NamingOrigin { feature: f.clone(), before: before.clone(), depth, mats, sheets });
         // Pieces a cut left are named after their faces, not the kernel's shell order (unless
         // the feature was saved when they were named in that order).
         if !f.shell_piece_order {