extend/pathname: restore old rmtree behaviour

Library/Homebrew/extend/pathname.rb

@@ -257,6 +257,17 @@ def stem
     File.basename(self, extname)
   end
 
+  # Like regular `rmtree`, except it never ignores errors.
+  #
+  # This was the default behaviour in Ruby 3.1 and earlier.
+  #
+  # @api public
+  sig { void }
+  def rmtree(**options)
+    FileUtils.rm_r(@path, **options)
+    nil
+  end
+
   # I don't trust the children.length == 0 check particularly, not to mention
   # it is slow to enumerate the whole directory just to see if it is empty,
   # instead rely on good ol' libc and the filesystem