Improve `is_word` function

[dpalmasan]

Currently is_word function receives as an argument a pos_tag:

https://github.com/dpalmasan/TRUNAJOD2.0/blob/master/src/TRUNAJOD/utils.py#L241

Would be better for usability purposes that it receives a spacy Token instead.

Acceptance criteria

• Signature for is_word is updated and input is a spacy Token
• Type hints updated properly
• No regressions in test cases

[dpalmasan]

Fixed on #65