[Feature] Compiler flags for any block

I think using compiler flags only for functions is too restrictive and should be broaden to all blocks.

For example this code:
```ab
main {
let x = "asd"

echo x as Num
}
```

Raises warning that it's not recommended to do such a cast and recommends adding `allow_absurd_cast` compiler flag for suppression, but it's not possible currently