feat(LS): Annotate all top level definitions code action

[ankddev]

Closes #4751
Add code action to add type annotation to all top level definitions.

Showcase

pub const answer = 42
pub fn add(x, y) {
  x + y
}
pub fn add_one(thing) {
  //     ^ Triggering "Annotate all top level definitions" code action here
  let result = add(thing, 1)
  result
}

would become:

pub const answer: Int = 42
pub fn add(x: Int, y: Int) -> Int {
  x + y
}
pub fn add_one(thing: Int) -> Int {
  let result = add(thing, 1)
  result
}

[giacomocavalieri]

Thank you, that's a great start! I left a couple of comments and questions inline

[giacomocavalieri]

Fantastic! I've left just two comments that need addressing, well done!

[GearsDatapacks]

Could we also have a test for partially annotated generic functions? For example:

pub fn wibble(a: a, b, c: c, d) {
  todo
}

[ankddev]

Hmm, interesting. Why it shows code action for annotated functions? It worked yesterday (I tested it in Zed and Neovim), but it doesn't now.
UPD: I found it

[giacomocavalieri]

Great, this looks good to me!! It only needs Louis' approval now :)

[ankddev]

Ah, CI was failed because of network issues