Mention User or Group on Deck Card description

[fitus85]

How to use GitHub

• Please use the 👍 reaction to show that you are affected by the same issue.
• Please don't comment if you have no relevant information to add. It's just extra noise for everyone subscribed to this issue.
• Subscribe to receive notifications on status change and new comments.

Describe the solution you'd like
I would prefer to also mention a user or group on the description of a deck card also. At the moment it is only possible for comments.