[Docs] Replace rst style double-backtick with md single-backtick (#27091)

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

tools/check_init_lazy_imports.py

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """Ensure we perform lazy loading in vllm/__init__.py.
-i.e: appears only within the ``if typing.TYPE_CHECKING:`` guard,
+i.e: appears only within the `if typing.TYPE_CHECKING:` guard,
 **except** for a short whitelist.
 """