Format file annotations

[BraisGabin]

This should be flagged:

@file:JvmName package foo.bar

and reformatted to

@file:JvmName

package foo.bar

I tried to create a PR myself to fix this but I can't find a neat way to handle all the cases.

The problem is that the file annotations are treated as normal annotations but they are different. They have its own rules in the coding conventions.