Update staking-v4.md

[katunopolis]

Updated a few sections in accordance with Marius Ciuca

Description of the pull request (what is new / what has changed)

Did you test the changes locally ?

• [ ] yes
• [x] no

Which category (categories) does this pull request belong to?

• [ ] document new feature
• [ ] update documentation that is not relevant anymore
• [x] add examples or more information about a component
• [ ] fix grammar issues
• [x] other