Merge pull request #431 from KenVanHoeylandt/patch-1

Fix for broken link to device API docs

docs/software/sw-design.md

@@ -5,5 +5,5 @@ This is a mini design doc for developing the meshtastic software.
 * Our [project board](https://github.com/orgs/meshtastic/projects/1) - shows what things we are currently working on and remaining work items for the current release.
 * [Power Management](power.md)
 * [Mesh algorithm](mesh-alg.md)
-* [Bluetooth API](bluetooth-api.md) and porting guide for new clients (iOS, python, etc...)
+* [Device API](device-api.md) and porting guide for new clients (iOS, python, etc...)
 * TODO: how to port the device code to a new device.