docs(priority-election): fix the property key

[diasonti]

Description

Fixed property key in the Priority Election section of Zeebe self-hosted docs, along with some minor grammar mistakes.

When should this change go live?

• This is a bug fix, security concern, or something that needs urgent release support.
• This is already available but undocumented and should be released within a week.
• This on a specific schedule and the assignee will coordinate a release with the DevEx team. (apply hold label or convert to draft PR)
• This is part of a scheduled alpha or minor. (apply alpha or minor label)
• There is no urgency with this change and can be released at any time.

PR Checklist

• My changes are for an already released minor and are in /versioned_docs directory.
• My changes are for the next minor and are in /docs directory (aka /next/).

• My changes require an Engineering review, and I've assigned the Engineering DRI or delegate.
• My changes require a technical writer review, and I've assigned @camunda/tech-writers as a reviewer.

[CLAassistant]

All committers have signed the CLA.

[akeller]

@diasonti thank you for signing out CLA! I've added our tech writers to review and will pull in a member of the Zeebe team as well. Thank you for your PR.

[lenaschoenburg]

Thanks, good catch with the config key 👍

[akeller]

Quick summary and link to the thread internally - depending on how the context handles double quotes, including them could make it part of the value (meaning instead of true the value is "true". There might be a context where you need double quotes.