Untrim: holes removed and a face restored to its natural bounds (#1150)

Adds surface.untrim (#761); the SurfaceUntrim feature is first saved in format 21.

crates/doc/src/feature_walk_tests/fixtures.rs

@@ -151,6 +151,7 @@ pub(super) fn fixtures() -> Vec<(&'static str, Value)> {
         ("surface_offset", json!({"type": "surface_offset", "faces": [o], "distance": "soff.distance", "tolerance": "soff.tolerance"})),
         ("unstitch", json!({"type": "unstitch", "body": "B"})),
         ("reverse_normal", json!({"type": "reverse_normal", "body": "B"})),
+        ("surface_untrim", json!({"type": "surface_untrim", "face": {"body": "B", "point": o}, "holes": [o], "outer": true})),
         ("surface_extend", json!({"type": "surface_extend", "body": "B", "edges": [o], "distance": "extend.distance"})),
         ("surface_trim", json!({"type": "surface_trim", "body": "B", "plane": plane("trim"), "keep": o})),
         ("move", json!({"type": "move", "bodies": ["B"], "translate": ["move.x", "move.y", "move.z"], "angle": "move.angle"})),

crates/doc/src/feature_walk_tests/golden_exprs.txt

@@ -325,6 +325,7 @@ surface_offset
   expressions: soff.distance, soff.tolerance
 unstitch
 reverse_normal
+surface_untrim
 surface_extend
   inputs:
     Distance = extend.distance (Length)

crates/doc/src/feature_walk_tests/golden_geometry.txt

@@ -150,6 +150,9 @@ unstitch
   moves: faces[0][0], faces[0][1], faces[0][2]
 reverse_normal
   moves: faces[0][0], faces[0][1], faces[0][2]
+surface_untrim
+  moves: face.point[0], face.point[1], face.point[2], holes[0][0], holes[0][1], holes[0][2]
+  face points: [0, 0, 0]
 surface_extend
   moves: edges[0][0], edges[0][1], edges[0][2]
 surface_trim

crates/doc/src/feature_walk_tests/golden_refs.txt

@@ -168,6 +168,8 @@ unstitch
   remap_bodies: body
 reverse_normal
   remap_bodies: body
+surface_untrim
+  remap_bodies: face.body
 surface_extend
   remap_bodies: body
 surface_trim