Deprecate --disable-log-requests and replace with --enable-log-requests (#21739)

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

vllm/utils/__init__.py

@@ -1668,6 +1668,12 @@ class FlexibleArgumentParser(ArgumentParser):
         # Enable the deprecated kwarg for Python 3.12 and below
 
         def parse_known_args(self, args=None, namespace=None):
+            if args is not None and "--disable-log-requests" in args:
+                # Special case warning because the warning below won't trigger
+                # if –-disable-log-requests because its value is default.
+                logger.warning_once(
+                    "argument '--disable-log-requests' is deprecated. This "
+                    "will be removed in v0.12.0.")
             namespace, args = super().parse_known_args(args, namespace)
             for action in FlexibleArgumentParser._deprecated:
                 if (hasattr(namespace, dest := action.dest)