unique tokens in query (#287)

Author: generall

fastembed/sparse/bm25.py

@@ -250,8 +250,8 @@ def query_embed(self, query: Union[str, Iterable[str]], **kwargs) -> Iterable[Sp
             tokens = self.tokenizer.tokenize(text)
             stemmed_tokens = self._stem(tokens)
             token_ids = np.array(
-                [self.compute_token_id(token) for token in stemmed_tokens],
-                dtype=np.float32,
+                list(set(self.compute_token_id(token) for token in stemmed_tokens)),
+                dtype=np.int32,
             )
             values = np.ones_like(token_ids)
             yield SparseEmbedding(indices=token_ids, values=values)