[Bug] Mail demand/output is displayed as 2^16-1 for some Residental houses

[Mariculous]

I have just found some courius bug about the displayed value of some residental houses in the "Build city buidings" menu.
Luckily I can tell that this wrong value seems to only affected in that build menu, when building the residental house, values are correct.

It seems to be not affected to my savegame, as I could reproduce this by creating a new game in 1750 and opening the "Build city buildings" menu in there.

Not all buildings are affected and I could not find any affected Shop or industrial building, at least not in 1750.

For me, in 1750 every single Residental house except fo the "House" is affected.

As this is not a critical bug, it is not pretty high priority to fix it.