[clang-format] Add spaces around the Verilog implication operator (#71352)

The Verilog implication operator `->` is a binary operator meaning
either the left hand side is false or the right hand side is true.
Previously it was treated as the C++ struct member operator.

I didn't even know it existed when I added the operator formatting part.
And I didn't check all the tests for all the operators I added. That is
how the bad test got in.