Metal bridge over air tiles

[RafeHaab]

Construction that allows to build metal grates over empty air tiles.

Summary

SUMMARY: Feature "Build metal bridges over open-air tiles"

Purpose of change

By request, I'm adding a way to create metallic bridges that require the tile to be empty air.

Describe the solution

Add a construction project that does it.

Describe alternatives you've considered

Wooden bridges, but someone suggested metal and I liked it better.

Testing

Additional context

[anothersimulacrum]

I don't think these should be added until there's a way to have proper supports.

[RafeHaab]

I don't think these should be added until there's a way to have proper supports.

You need some kind of support to start building on the second level, actually. Else how do you even get there?

[FuelType-Memes]

I think @anothersimulacrum means adding "pre_special": "check_support", otherwise you can build infinitely long metal bridges

[kevingranade]

I agree with @anothersimulacrum , indefinitely long bridges are not ok, and this (probably accidentally) allows them.

[RafeHaab]

Ok, what's failing now?

[FuelType-Memes]

It says right there in the details. For example JSON style check gives this error right at the bottom:

data/json/construction.json needs to be linted
Please read doc/JSON_STYLE.md

[kevingranade]

Suggested change

	"components": [ [ [ "pipe", 12, "sheet_metal", 1 ] ] ],
	"components": [ [ [ "pipe", 12 ] ], [ [ "sheet_metal", 1 ] ] ],

[kevingranade]

Seems fine now except for the json load errors.