Let inputs of fast tokenizers be tuples as well as lists
# What does this PR do?

Fixes #19882
Not sure if this was an oversight when introducing fast tokenizers or if there is a real reason for not accepting tuples as well as list here (which is the case everywhere else from a quick search). We'll see if the CI picks something failing but it looks like it fixes the issue.
_The documentation is not available anymore as the PR was closed or merged._