vocab : add tokenizer support for jina-embeddings-v2-base-zh (#18756)

* vocab : add jina-embeddings-v2-base-zh (whitespace tokenizer)

* lowercase defaults to true

* type fix

---------

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

gguf-py/gguf/gguf_writer.py

@@ -1110,6 +1110,9 @@ class GGUFWriter:
 
         self.add_string(Keys.Tokenizer.CHAT_TEMPLATE, value)
 
+    def add_normalizer_lowercase(self, value: bool) -> None:
+        self.add_bool(Keys.Tokenizer.NORMALIZER_LOWERCASE, value)
+
     def add_eot_token_id(self, id: int) -> None:
         self.add_uint32(Keys.Tokenizer.EOT_ID, id)