Air Gap Fix

This datapack simply makes the block connect when a sign, banner or
other wall block is placed on it. This fixes the "air gap" that forms
when normally placing these blocks, which always looks a bit odd, the
blocks just floating there.


Blocks:
All fences, walls, glass panes, bars.


Attachables:
All signs, banners, player heads, end rod, lightning rods, item frames.


When removing an item frame it doesn't update the block, so it stays
extended. I left that in because you can use that as a feature, if you
want a fence extended somewhere for example.


Let me know if you have any issues with this datapack or if there's other air gaps I should fix!