fix link to sbughz radio

README.md

@@ -7,4 +7,4 @@ Kickstarter page: [kickstarter.com](https://www.kickstarter.com/projects/flipper
 
 # Modules
 
-* [Sub-1 GHz radio](/wiki/sub-1ghz-radio)
+* [Sub-1 GHz radio](wiki/sub-1ghz-radio.md)