Add a note to clarify header.Set behavior on cookies

[sigmundxia]

Hi Developers,

As described in this issue, currently header.Set does not reset but adds cookies. This pull request attempts to fix this so that header.Set resets cookies instead of adding them.

Feel free to let me know if there are any further changes you would like me to make.

Best regards!

[erikdubbelboer]

This would be a backwards incompatible change for anyone using header.Set with Cookie. I don't think we should just change it because of that. I think a better solution would be to really make this clear in the documentation that you need to delete the 'Cookie' header before setting it if you don't want to add.

[sigmundxia]

Indeed, changing the behavior of this method may cause compatibility issues for downstream software. I will try to make direct improvements to gofiber downstream. So, should this pull request be closed? Or should I undo all changes here and add a note about cookies in the code comments?

[erikdubbelboer]

Yeah sorry lets change this pull to only add a note to the documentation to clarify this behavior. Thanks!

[sigmundxia]

Yeah sorry lets change this pull to only add a note to the documentation to clarify this behavior. Thanks!

No problem, I also think a change to the description would be ideal 😊 I've made the changes, let me know if there are any further changes needed!

[erikdubbelboer]

Thanks, it's good!