Improve how the sky and block lights are combined in the shader.

[IntegratedQuantum]

This is an interesting one.
So far placing a lightsource in broad daylight (or in a brightly lit surface cave) had no effect at all.
With this patch placing a torch or another light source actually makes things (slightly) brighter.
Now, since the peak brightness is capped at one, this mostly affects the shadow areas, this does make the ambient occlusion weaker in these areas. But for dimmer light sources like the torch the difference is small and for brighter light source it seems reasonable that the ambient occlusion is reduced when the light is coming from multiple source.

This would help distinguish weak lights in a bright night (as noticed in #2440 (comment))

@ikabod-kee @careeoki I would like your opinions here as well. I decided to make this an independent PR in case #2440 is rejected, since I think this is a decent improvement either way.

[careeoki]

I like this, it makes it more obvious that blocks are emmisive during the day. And from what I can tell it helps the problem I mentioned in the other PR.

[ikabod-kee]

This is unrelated, but what would happen if we removed the cap or made it go beyond 1?

[IntegratedQuantum]

intense bloom

[ikabod-kee]

May I see it?

[IntegratedQuantum]