remove two tokens that should not be suppressed
# What does this PR do?
As mentionned in #20123, two tokens `'` and `-` were supressed. This was probably from the [late commit](https://github.com/openai/whisper/commit/8cf36f3508c9acd341a45eb2364239a3d81458b9) that appeared after I started working on it. 
_The documentation is not available anymore as the PR was closed or merged._