Fillet: refuse only crossed faces the round makes, not ones the body had (#1488) (#1517)

Thanks @erkexzcx.

crates/engine/src/tests.rs

@@ -316,6 +316,7 @@ mod loft_spacing;
 mod mirror_planes;
 #[cfg(not(target_arch = "wasm32"))]
 mod native_cad_import;
+mod nudge_slivers;
 mod path_scope;
 mod pleat_join;
 mod primitive_points;