Studio/time announcer: return ealry if time is None. Re #155.

Mypy: because time announcer is typically called from time commands after obtaining Studio API results for track duration, make sure to catch the case where time integer can be None, and if yes, return early. This change resolves type mismatch for time commands.

addon/appModules/splstudio/__init__.py

@@ -1223,9 +1223,12 @@ def terminate(self):
 	# 6.0: Split this into two functions: the announcer (below) and formatter.
 	# 7.0: The ms (millisecond) argument will be used when announcing playlist remainder.
 	# 16.12: Include hours by default unless told not to do so.
+	# #155 (21.03): time can be None, in which case it will do nothing.
 	def announceTime(
 			self, t: int, offset: Optional[int] = None, ms: bool = True, includeHours: Optional[bool] = None
 	) -> None:
+		if t is None:
+			return
 		if t <= 0:
 			ui.message("00:00")
 		else: