[Feature] Add docs of batch invariance and make some extra operators patch (#6910)

### What this PR does / why we need it?

This PR add docs of batch invariance and make some extra operators
according to validation result.
please see https://github.com/vllm-project/vllm-ascend/issues/5487 to
track progress.

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?

- vLLM version: v0.16.0
- vLLM main:
15d76f74e2

---------

Signed-off-by: Ronald1995 <ronaldautomobile@163.com>

vllm_ascend/utils.py

@@ -258,10 +258,19 @@ def enable_custom_op():
     Enable lazy init for vllm_ascend_C to avoid early initialization of CANN's RTS component.
     Ensure that ASCEND_RT_VISIBLE_DEVICES can be dynamically modified before torch.npu.set_device().
     """
+    from vllm.model_executor.layers.batch_invariant import vllm_is_batch_invariant
+
     global _CUSTOM_OP_ENABLED
 
     if _CUSTOM_OP_ENABLED is not None:
         return _CUSTOM_OP_ENABLED
+
+    # There are some customed operators which aren't implemented
+    # with batch invariant in vllm-ascend, we need to disable them.
+    if vllm_is_batch_invariant():
+        _CUSTOM_OP_ENABLED = False
+        return _CUSTOM_OP_ENABLED
+
     try:
         # isort: off
         # register custom ops into torch_library here