Fix #4938: Dynamic symbols keep per-instance appearance linked to the symbol

crates/doc/src/node/extras.rs

@@ -63,6 +63,9 @@ pub struct NodeExtras {
     pub compound_shape: bool,
     /// As a member of a compound shape, how this object combines with the members below it.
     pub shape_mode: crate::ShapeMode,
+    /// As an instance of a dynamic symbol, its own appearance changes to objects of the symbol's
+    /// art (see [`crate::symbol_overrides`]); empty for none.
+    pub symbol_overrides: Vec<crate::SymbolOverride>,
 }
 
 /// No extras: what [`Node::extras`] gives for a node without any.
@@ -87,6 +90,7 @@ pub(super) static NO_EXTRAS: NodeExtras = NodeExtras {
     colorize: None,
     compound_shape: false,
     shape_mode: crate::ShapeMode::Add,
+    symbol_overrides: Vec::new(),
 };
 
 /// A node's [`NodeExtras`], if it has any ([`Node::extras`]). Extras that are all unset equal