Format header files

In my PR updating clang-format, I forgot to also format the headers.

src/heartratetask/HeartRateTask.h

@@ -8,9 +8,11 @@ namespace Pinetime {
   namespace Drivers {
     class Hrs3300;
   }
+
   namespace Controllers {
     class HeartRateController;
   }
+
   namespace Applications {
     class HeartRateTask {
     public: