Allow single quotes "'" and hyphens "-"

Remove single quotes `'` (id 6) and hyphens `-` (id 12) from `suppress_tokens`. These tokens should **not** be suppressed during generation. They are accepted as valid generated tokens in the official Whisper repo:
https://github.com/openai/whisper/blob/eff383b27b783e280c089475852ba83f20f64998/whisper/tokenizer.py#L258

Check that we're removing the right tokens:
```python
from transformers import WhisperTokenizer

tokenizer = WhisperTokenizer.from_pretrained("openai/whisper-medium.en")

print(tokenizer.decode(6))
print(tokenizer.decode(12))
```

**Print Output:**
```
'
-
```

config.json

@@ -42,12 +42,10 @@
   "suppress_tokens": [
     1,
     2,
-    6,
     7,
     8,
     9,
     10,
-    12,
     14,
     25,
     26,