Add new visitor for Prism::ConstantPathNode

lib/spoom/deadcode/indexer.rb

@@ -174,6 +174,18 @@ def visit_constant_read_node(node)
         reference_constant(node.name.to_s, node)
       end
 
+      sig { override.params(node: Prism::ConstantPathNode).void }
+      def visit_constant_path_node(node)
+        # In prism 0.28.0, ConstantPathNode was updated to have no children
+        # and instead store the constant name as a string.
+        if node.respond_to?(:name)
+          visit(node.parent) if node.parent
+          reference_constant(node.name.to_s, node)
+        end
+
+        super
+      end
+
       sig { override.params(node: Prism::ConstantWriteNode).void }
       def visit_constant_write_node(node)
         name = node.name.to_s