Artifact on letter 'a' in "Validateer 2" in Sequence diagram of on-boarding a new validateer 

The picture https://github.com/integritee-network/docs/blob/main/.gitbook/assets/4.3.2.5%20(1).jpg used in [4.3.2.5-on-boarding-of-new-validateers](https://github.com/integritee-network/docs/blob/main/4-development/4.3-design/4.3.1-l2-sidechain/4.3.2.5-on-boarding-of-new-validateers.md) has its letter 'a' crossed by the blue line under it.