Update Optional[x] -> x | None and Union[x, y] to x | y (#26633)

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

tests/kernels/attention/test_attention.py

@@ -2,7 +2,6 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import random
-from typing import Optional
 
 import pytest
 import torch
@@ -50,7 +49,7 @@ def ref_masked_attention(
     key: torch.Tensor,
     value: torch.Tensor,
     scale: float,
-    attn_mask: Optional[torch.Tensor] = None,
+    attn_mask: torch.Tensor | None = None,
 ) -> torch.Tensor:
     attn_weights = scale * torch.einsum("qhd,khd->hqk", query, key).float()
     if attn_mask is not None:
@@ -69,7 +68,7 @@ def ref_single_query_cached_kv_attention(
     block_tables: torch.Tensor,
     seq_lens: torch.Tensor,
     scale: float,
-    alibi_slopes: Optional[torch.Tensor],
+    alibi_slopes: torch.Tensor | None,
 ) -> None:
     num_query_heads = query.shape[1]
     num_kv_heads = value_cache.shape[1]
@@ -415,7 +414,7 @@ def ref_multi_query_kv_attention(
     key: torch.Tensor,
     value: torch.Tensor,
     scale: float,
-    alibi_bias: Optional[list[torch.Tensor]],
+    alibi_bias: list[torch.Tensor] | None,
     dtype: torch.dtype,
 ) -> torch.Tensor:
     num_seqs = len(cu_seq_lens) - 1