Announcement: new moderation features

[hobovsky]

Not all features are of any interest for regular users, but some of them would be worth to be announced, so users know that some specific issue can be addressed in general:

[...]

• Let mods hide solution group from the list (audited)
• Let mods invalidate solution group without verifying (audited)
• Let mods recalculate buggy beta votes (audited)
• Let mods unpublish beta kata (audited)
• Let mods remove rank assessments and votes (audited)

[...]

• inform users that some issues are now possible to be handled
• ask users to report problematic instances, so mods could handle them
• say "thanks" to maintainers who did the hard work of implementing these

[hobovsky]

Additional point: link to docs on moderation:

• https://docs.codewars.com/community/moderation/
• the result of Reference: list of moderator features docs#250

[hobovsky]

My initial idea behind this post was that #18 could be published before codewars/docs#250 gets realized, leaving community without details. But now, since #18 has not been published yet, and it already links to the result of codewars/docs#251, separate post with the announcement of specific features might be not necessary anymore (until new ones will be provided, that is).