Fix LLaMATokenizer naming
# What does this PR do?

Simple fix for the naming of LLaMATokenizer class
The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_22217). All of your documentation changes will be reflected on that endpoint.<|||||>Ah ok, it was preventing me from loading a saved model because of the capitalization change so thought it was a mistake. In that case I'll be closing this, for anyone coming across the same issue ("Tokenizer class LLaMATokenizer does not exist or is not currently imported.") they can use my fork to load them for now.