[WIP] Update invoicing use case page based on review feedback

[Copilot]

Thanks for the feedback on #26. I've created this new PR, which merges into #26, to address your comment. I will work on the changes and keep this PR's description up to date as I make progress.

Original PR: #26
Triggering review: #26 (comment)

@copilot ✅ Fixed - updated to link to /api-features/recurring-payments which exists

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[MantisClone]

this is already fixed