Rework contribution section

[CaptainSifff]

Oh well, I looked into the Credit system again, and I only thought....
Well, how does this fit to us?
So I wrote a generic text to tick that box, and went on to detail those parts that I could remember, which you have contributed over the past years.
Feel free to raise your opinions.

I also accept private E-Mail, if I took a wrong direction somewhere....

Now comes the pleasure of finding all your github usernames ....

[CaptainSifff]

Pinging @sdruskat , @tobyhodges @annalenalamprecht , @HeidiSeibold , @hvwaldow , @samumantha
As I found out there's a limit of 15 reviewers on github....

[jngrad]

I predict there will be a lot of small changes during review. In order to reduce notifications, we could apply suggested changes in batches, i.e. 1 commit for multiple review comments. 😉 This option is only visible in the Changes tab, afaik.

[CaptainSifff]

the spell-checker will be made happy by the PR of @jcohen02 .

[mhagdorn]

expanded shortened verbs

[annalenalamprecht]

I cannot find it back right now, but @MakisH pointed out earlier that "helped us" (and similar wording) sounds a bit odd when mentioning people who are also on the list of authors. Simply removing the "us" from these sentences would solve the issue.

Edit: Seeing now that @knarrff was just making changes in this direction. Thanks!!

[CaptainSifff]

I'm beginning the publication process, thereby closing this box as of now.

[sdruskat]

Thanks for the ping, I‘ll get to review this week (before Friday).