Should tanween dammah be written with a line over it?

[mustafa0x]

As that's how it looks in the Medinah mushaf.

A comparison:

[nailhuseyn]

For me it makes more sense, since people get used to symbols. If it is not complicated we should do it. Allahu alam.

[khaledhosny]

Both are acceptable AFAIK, the former is more common in typography.