[Lint]Style: Convert root, benchmarks, tools and docs to ruff format (#5843)

### What this PR does / why we need it?
Description
This PR fixes linting issues in the root directory, benchmarks/, tools/
and docs/ to align with the project's Ruff configuration.

This is part of a gradual effort to enable full linting coverage across
the repository. The corresponding paths have been removed from the
exclude list in pyproject.toml.

### Does this PR introduce _any_ user-facing change?

### How was this patch tested?

- vLLM version: v0.13.0
- vLLM main:
2f4e6548ef

---------

Signed-off-by: root <root@LAPTOP-VQKDDVMG.localdomain>
Co-authored-by: root <root@LAPTOP-VQKDDVMG.localdomain>

tools/check_python_src_init.py

@@ -36,8 +36,8 @@ def check_init_file_in_package(directory):
         return False
 
     # If any .py file exists, we expect an __init__.py
-    if any(f.endswith('.py') for f in files):
-        init_file = os.path.join(directory, '__init__.py')
+    if any(f.endswith(".py") for f in files):
+        init_file = os.path.join(directory, "__init__.py")
         if not os.path.isfile(init_file):
             return False
     return True
@@ -62,9 +62,7 @@ def main():
         all_missing.update(missing)
 
     if all_missing:
-        print(
-            "❌ Missing '__init__.py' files in the following Python package directories:"
-        )
+        print("❌ Missing '__init__.py' files in the following Python package directories:")
         for pkg in sorted(all_missing):
             print(f" - {pkg}")
         sys.exit(1)