Convert formatting to use ruff instead of yapf + isort (#26247)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

vllm/beam_search.py

@@ -18,6 +18,7 @@ class BeamSearchSequence:
     The text field is optional and will only be filled when the sequence is
     about to be returned to the user.
     """
+
     # The tokens include the prompt.
     tokens: list[int]
     logprobs: list[dict[int, Logprob]]
@@ -36,11 +37,11 @@ class BeamSearchOutput:
     It contains the list of the best beam search sequences.
     The length of the list is equal to the beam width.
     """
+
     sequences: list[BeamSearchSequence]
 
 
 class BeamSearchInstance:
-
     def __init__(
         self,
         prompt_tokens: list[int],
@@ -79,9 +80,9 @@ def get_beam_search_score(
 
 
 def create_sort_beams_key_function(eos_token_id: int, length_penalty: float):
-
     def sort_beams_key(x: BeamSearchSequence) -> float:
-        return get_beam_search_score(x.tokens, x.cum_logprob, eos_token_id,
-                                     length_penalty)
+        return get_beam_search_score(
+            x.tokens, x.cum_logprob, eos_token_id, length_penalty
+        )
 
     return sort_beams_key