[Misc][Doc] Add missing comment for LLM (#20285)

Signed-off-by: Lifan Shen <lifans@meta.com>

vllm/entrypoints/llm.py

@@ -132,6 +132,14 @@ class LLM:
         hf_overrides: If a dictionary, contains arguments to be forwarded to the
             HuggingFace config. If a callable, it is called to update the
             HuggingFace config.
+        mm_processor_kwargs: Arguments to be forwarded to the model's processor
+            for multi-modal data, e.g., image processor. Overrides for the
+            multi-modal processor obtained from `AutoProcessor.from_pretrained`.
+            The available overrides depend on the model that is being run.
+            For example, for Phi-3-Vision: `{"num_crops": 4}`.
+        override_pooler_config: Initialize non-default pooling config or
+            override default pooling config for the pooling model.
+            e.g. `PoolerConfig(pooling_type="mean", normalize=False)`.
         compilation_config: Either an integer or a dictionary. If it is an
             integer, it is used as the level of compilation optimization. If it
             is a dictionary, it can specify the full compilation configuration.