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## Summary
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importantly what they aim to achieve -->
This clarifies in the contributing docs which project is being
contributed to and which repo to work against - previously it said just
"Home Assistant" which could be confusing.
This also updates the repo URL in the contributing docs and at the same
time several code comments that also used the older repo URL.
## Screenshots
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## Link to pull request in Documentation repository
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corresponding pull request in the Companion App Documentation repository
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Documentation: home-assistant/companion.home-assistant#
## Any other notes
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Based on Discord conversation with @zacwest, expanding CONTRIBUTING.md to give newcomers some pointers to how to learn Swift. This could be useful coming off the heels of the Home Assistant Conference 2020, in which attendees were invited to learn Swift and contribute back.
