fix: properly remove nested empty directories

feather.py

@@ -248,10 +248,18 @@ def remove_html_for_item(config, item_json, ignore_deleted=False):
 def remove_empty_html_directories(config):
     # Remove empty directories in the HTML directory
     html_root = config.html_root
+    removed_directories = set()
     for (dirpath, dirnames, filenames) in html_root.walk(top_down=False):
         if dirpath != html_root:
-            if len(dirnames) == 0 and len(filenames) == 0:
+            is_empty = len(filenames) == 0
+            if is_empty and len(dirnames) > 0: # some subdirectories may have been removed in an earlier iteration
+                for subdirname in dirnames:
+                    if dirpath / subdirname not in removed_directories:
+                        is_empty = False
+                        break
+            if is_empty:
                 dirpath.rmdir()
+                removed_directories.add(dirpath)
 
 def synchronize(config, client_session):
     # Do a full feather update