Add raw_data proc to builtin/builtin.odin

[thetarnav]

Fixes #417

This works, but not without issues.

It does autocomplete, but it also shows completions for the private procs.

The hover info for returned value works only for a string source, every other overload just doesn't work.

[DanielGavin]

I think it works in rename branch. Atleast some of them. Don't think the simd one is supported yet.

[thetarnav]

And do you know why the private procs are showing up? it is because builtin is being added to the „global scope” or something?

[DanielGavin]

Have you tried doing private="file"? It might treat the builtin as in the same package as the current one being edited.

[thetarnav]

it does indeed help with autocomplete, but for some reason it completely disables hover info

[DanielGavin]

I'll have a look at that later.