Feature fields: a type for each role (Expr, BodyName, FacePick…) (#1273)

Thanks @jijinbei.

crates/doc/src/project.rs

@@ -261,8 +261,11 @@ fn resolve_uncached(
         // Its path is a curve of its own sketch: set with the sketch (`Sketch::text_source_geometry`).
         LinkSource::Text { .. } => return Err(DocError::Invalid("a text on a path is set with its sketch".into())),
         LinkSource::Plane { name } => {
-            let pr =
-                if Plane::named(name).is_some() { PlaneRef::Origin { name: name.clone() } } else { PlaneRef::Construction { name: name.clone() } };
+            let pr = if Plane::named(name).is_some() {
+                PlaneRef::Origin { name: name.clone() }
+            } else {
+                PlaneRef::Construction { name: name.clone().into() }
+            };
             let other = doc.resolve_plane_in(vals, &pr, 0, Some(st)).map_err(|_| lost(&format!("plane {name}")))?;
             plane_trace(plane, &other).into_iter().collect()
         }