error: unable to open template file '$DIR/templates/a_file_that_is_actually_a_folder.html': Is a directory (os error 21)
 --> YouCannotIncludeFolders.txt:1:2
       " include \"a_file_that_is_actually_a_folder.html\" %}"
 --> tests/ui/include-a-folder.rs:4:34
  |
4 | #[template(ext = "txt", source = r#"{% include "a_file_that_is_actually_a_folder.html" %}"#)]
  |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^