Rib/Web: grow along the sketch normal (#2056) (#2057)

Thanks @pablopeza.

crates/doc/src/format/pending/rib-normal-direction.rs

@@ -0,0 +1,4 @@
+//! A Rib or Web can grow along the sketch normal (`normal: true`): the wall is `thickness` wide
+//! across its curves in the sketch plane and runs from the sketch toward the body. Older designs
+//! need no transformation: a rib without `normal` grows across the sketch plane as before; 0.14.x
+//! asks for an update instead of building a normal rib in the plane.