Add “current” for /iteration

Introduction

With #196795 (closed) it was made possible to add iterations by quick actions. It should be possible to assign the current iteration without remembering the name of the current iteration. In some cases, referring to the current iteration is already possible (#196804 (closed)).

Proposal

/iteration Current assigns the current iteration.

Advantages

• No need to remember the name of the current iteration
• It can be used in description templates