Fix empty-choice-indentation bug

[Jowan-Spooner]

Reported by a user on discord, having an empty choice before an indentation change would incorreclty calculate the amount of end branches needed.

Example timeline of failure:

if {RedWandCount} > 0 or {BlueWandCount} > 0 or {GreenWandCount} > 0:
	The pedestal is empty.
	- Place red wand [if {RedWandCount} > 0][else="hide"]
	- Place blue wand [if {BlueWandCount} > 0][else="hide"]
	- Place green wand [if {GreenWandCount} > 0][else="hide"]
else:
	The pedestal is empty and you can't do anything about it.
The end
[end_timeline]

Would fail previously, but now works.

[coppolaemilio]

Thanks!