Revert "Using serde (serde_pyo3) to get __str__ and __repr__ easily."

This reverts commit 86138337fc.

bindings/python/src/normalizers.rs

@@ -44,8 +44,8 @@ impl PyNormalizedStringMut<'_> {
 /// Normalizer will return an instance of this class when instantiated.
 #[pyclass(dict, module = "tokenizers.normalizers", name = "Normalizer", subclass)]
 #[derive(Clone, Serialize, Deserialize)]
-#[serde(transparent)]
 pub struct PyNormalizer {
+    #[serde(flatten)]
     pub(crate) normalizer: PyNormalizerTypeWrapper,
 }