docs: remove unnecessary double quotation marks

[otms61]

Description

--db-repository option contained extra double quotation marks, which were making the cli reference look bad.
So this PR has removed unnecessary double quotations.

Related issues

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).