Fix compress function

[chetanyb]

Fixes compilation errors discovered during ssz.zig integration:

• Remove invalid message parameter from assert() call (std.debug.assert only accepts boolean)
• Fix type mismatch in compress feed-forward: convert input to Montgomery form before addition
• Replace non-existent fromMontgomery() with toNormal() method
• Return proper array type instead of slice

[ch4r10t33r]

This looks good. Should we also include a test for this? I am surprised this compilation error wasn't caught before. Also please can you bump the version?

[chetanyb]

This looks good. Should we also include a test for this? I am surprised this compilation error wasn't caught before. Also please can you bump the version?

should we add tests to this PR itself or should I make a separate one for that?
Let's update the version post the tests? So the next release would also have substantial changes including your field ones.

[ch4r10t33r]

This looks good. Should we also include a test for this? I am surprised this compilation error wasn't caught before. Also please can you bump the version?

should we add tests to this PR itself or should I make a separate one for that? Let's update the version post the tests? So the next release would also have substantial changes including your field ones.

I would prefer you adding tests to this PR itself. But yes, I agree we can release a new version once you are satisfied after testing.

[chetanyb]

@ch4r10t33r can we get this merged first? Will raise the test PR separately. This way we all have these changes and I can even get the ssz integration PR out

[ch4r10t33r]

Sounds good to me.