Update Acknowledgments

[c2bo]

I'd like to add the people that have contributed/provided feedback in the past few weeks/months. Please give a thumbs up / comment here if you are ok with being mentioned in the Acknowledgments section.

I might have forgotten people - please comment if you think someone else should be added.

@rohanmahy - done
@steffenschwalm
@Denisthemalice
@sschulz-t
@cre8 - done
@mickrau - done
@hannestschofenig - done
@wbl
@rifaat-shekh-yusef - done

(also fix Giuseppe's spelling)