Switch and Pushbutton: add comment re logic.

Author: peterhinch

v3/primitives/pushbutton.py

@@ -104,4 +104,5 @@ async def buttoncheck(self):
                         self._ld.stop()  # Avoid interpreting a second click as a long push
                     self._dblran = False
             # Ignore state changes until switch has settled
+            # See https://github.com/peterhinch/micropython-async/issues/69
             await asyncio.sleep_ms(Pushbutton.debounce_ms)

v3/primitives/switch.py

@@ -39,4 +39,5 @@ async def switchcheck(self):
                 elif state == 1 and self._open_func:
                     launch(self._open_func, self._open_args)
             # Ignore further state changes until switch has settled
+            # See https://github.com/peterhinch/micropython-async/issues/69
             await asyncio.sleep_ms(Switch.debounce_ms)