doc: the model pane's skins link points at the struct that has them

`doc-links` was the last red gate, on one link dating from the fork's import
(`81d96af3`): `script::types.rs`'s `QuadContent::ModelPane::skins` cited
`widget::kinds::ModelState::skins`, a field that never existed on that struct. The
three creature skin variations live on `script::CreatureModelView`, which is what
a display id resolves to for a pane, so the link now goes there — by the public
re-export rather than through the private `model` module.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SgstFWtn1RxEJ5kVrpgYwn

crates/benilla-ui/src/script/types.rs

@@ -121,8 +121,8 @@ pub enum QuadContent {
         /// The `SetModel` file; `None` for a unit pane or an empty one.
         model: Option<String>,
         /// The creature skin variations for a pane showing a display id
-        /// ([`crate::widget::kinds::ModelState::skins`]); all `None` for an ordinary file, whose
-        /// batches name their own textures.
+        /// ([`crate::script::CreatureModelView::skins`]); all `None` for an ordinary file,
+        /// whose batches name their own textures.
         skins: [Option<String>; 3],
         /// `PlayerModel:SetUnit`'s subject, resolved this frame; `None` for a file pane, an empty
         /// one, or a token that names nothing right now.