access parent through ancestors

I'm removing the parent variable here and access the parent ancestor
directly through the ancestors variable. This allows me to move the
check if a node has a root constant fully into a private method.

Author: doodzik

lib/packwerk/const_node_inspector.rb

@@ -10,13 +10,11 @@ class ConstNodeInspector
 
     def constant_name_from_node(node, ancestors:)
       return nil unless Node.constant?(node)
-
       # Only process the root `const` node for namespaced constant references. For example, in the
       # reference `Spam::Eggs::Thing`, we only process the const node associated with `Spam`.
-      parent = ancestors.first
-      return nil if parent && Node.constant?(parent)
+      return nil if root_constant?(ancestors)
 
-      if constant_in_module_or_class_definition?(node, parent: parent)
+      if constant_in_module_or_class_definition?(node, ancestors: ancestors)
         fully_qualify_constant(node, ancestors: ancestors)
       else
         begin
@@ -29,8 +27,13 @@ def constant_name_from_node(node, ancestors:)
 
     private
 
-    def constant_in_module_or_class_definition?(node, parent:)
-      if parent
+    def root_constant?(ancestors)
+      parent = ancestors.first
+      parent && Node.constant?(parent)
+    end
+
+    def constant_in_module_or_class_definition?(node, ancestors:)
+      if (parent = ancestors.first)
         parent_name = Node.module_name_from_definition(parent)
         parent_name && parent_name == Node.constant_name(node)
       end