formula: fix alias/generic/prepend std_cmake_args issue. #18364

Seen in: Homebrew/homebrew-core#191090 (comment) There's a missing signature issue here due to the `generic_*` aliasing we're doing. With prepend, though: this is no longer needed and we can use `super` instead which is more idiomatic and nicer overall. This pattern should probably be applied in other places but: let's try this targetting fix for here first.