Add :nodoc: to Pathname#remove_entry

Fix rdoc-coverage failure by marking the private helper method
as :nodoc:.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hsbt

pathname.rb

@@ -1475,7 +1475,7 @@ def self.mktmpdir
 
   private
 
-  def remove_entry(path)
+  def remove_entry(path) # :nodoc:
     st = File.lstat(path)
     if st.directory?
       Dir.each_child(path) do |child|