Tokenizers not model-agnostic

I believe that the library's support models are based on tokenization and not model brand.

For example, using any of the latest Falcon models should work because they run on `PreTrainedTokenizerFast`, however, the following error arises:

```
NotImplementedError: Tokenizer not supported: PreTrainedTokenizerFast
```

This seems to be because the library recognizes models based on their path or title as opposed to their tokenizer type, and so `tiiuae/Falcon3-1B-Base` is unsupported, even though it should not be. The solution is to compare the loaded tokenizer to a list of supported tokenizer classes instead of focusing on naming conventions.