fix: empty extension files

init.lua

@@ -212,7 +212,7 @@ local render_numbers = ya.sync(function(_, mode, styles, resizable_entity_childr
 					entity.highlights = function(entity_highlight_self)
 						local name = entity_highlight_self._file.name:gsub("\r", "?", 1)
 						local tail = entity_highlight_self._file.cha.is_dir and ""
-							or ("." .. entity_highlight_self._file.url.ext(entity_highlight_self._file.url))
+							or ("." .. (entity_highlight_self._file.url.ext(entity_highlight_self._file.url) or ""))
 						local max_length = utf8.len(name) or 0
 						for _, c in ipairs(entity_highlight_self._children) do
 							if c[1] and type(c[1]) == "string" and c[1] == "highlights" and c.resizable then