Fix unused argument warnings on writeToBiSignal#

[leonschoorl]

Any usage of writeToBiSignal would result in:

Warning: The Haskell implementation of primitive Clash.Signal.BiSignal.writeToBiSignal# isn't using argument #1, but the corresponding primitive blackbox does.
This can lead to incorrect HDL output because GHC can replace these arguments by an undefined value.

Warning: The Haskell implementation of primitive Clash.Signal.BiSignal.writeToBiSignal# isn't using argument #3, but the corresponding primitive blackbox does.
This can lead to incorrect HDL output because GHC can replace these arguments by an undefined value.

Warning: The Haskell implementation of primitive Clash.Signal.BiSignal.writeToBiSignal# isn't using argument #4, but the corresponding primitive blackbox does.
This can lead to incorrect HDL output because GHC can replace these arguments by an undefined value.

This fixes that with some bang patterns on writeToBiSignal#.

I was a little afraid this might result in loops in haskell simulation.
But I've tested the manually test all three Counter* tests in Haskell simulation both inside clashi, and when compiled to executables.

Still TODO:

• Write a changelog entry (see changelog/README.md)
• Check copyright notices are up to date in edited files

[leonschoorl]

Mmm, my fear wasn't unfounded after all.
It is too strict for the clash-cores SPI test, but only using when ghc-9.0.

But Christiaans suggestion fixes the problem.

[christiaanb]

LGTM