```
  File "/Users/mcc/work/f/template-fpga/.venv/lib/pypy3.10/site-packages/amaranth/hdl/ast.py", line 1645, in __getitem__
    key = None if key is None else self._map_key(key)
                                   ^^^^^^^^^^^^^^^^^^
  File "/Users/mcc/work/f/template-fpga/.venv/lib/pypy3.10/site-packages/amaranth/hdl/ast.py", line 1836, in __init__
    raise TypeError("Object {!r} is not an Amaranth signal".format(signal))
TypeError: Object (const 16'd46973) is not an Amaranth signal
```
So if you tell the simulator to plot a const, it throws an error. How intentional is this?