remove C subgrammar for `emit`

[metagn]

For some reason this is buggy, using {.emit: [a, b, c].} completely removes highlighting of some files on github.

Keeping these commented as they may be reused for something like cLang"""..."""

[Araq]

We need this patch though, on some files the highlighting is unusable when you use something like .emit: [x, " = ", b]