remove InProcessKernel from top-level kernel.inprocess

avoid circular import

IPython/kernel/inprocess/__init__.py

@@ -4,7 +4,7 b' from .channels import ('
     InProcessStdInChannel,
     InProcessHBChannel,
 )
-from .ipkernel import InProcessKernel
+
 from .client import InProcessKernelClient
 from .manager import InProcessKernelManager
 from .blocking import BlockingInProcessKernelClient