Fix format mistake in string repr of tokenizer objects (#34493)
* fix repr string format for tokenizer objects
The repr of tokenizer tokens looks confusing and just stupid, like this: `Tokenizer(...), added_tokens_decoder={1: ..., 2: ...}`. The dict that is the value of the added_tokens_decoder attribute is outside of the parentheses of the tokenizer object, whereas all other attributes are inside the parentheses like they should be.
This commit fixes this bug.
* cos: add newline before closing parenthesis of repr string