Add annotation information

[tdroxler]

For new comers, it would be nice if they could get more information about annotations. for example in:

Contract MyContract() {
  @using(checkExternalCaller = false)
  pub fn function_a(boolean: Bool) -> () {
  }
}

They should be able to jump to definiton of @using or checkExternalCaller (latter having the hover) to see more doc.

Currently the annotations are defined in Parser file in the full node, but we only have the keys as String.
We could have something similar to BuiltIn, where doc comes alongside the types.

I experimented a bit by first extracting RalphAnnotation in a separate file and then adding some doc field to the annotation.

I also show in ralph-lsp that we can find the corresponding annotation and doc when requesting definition of checkExternalCaller.

So I think we could have something similar to the built-in function and std-interface. We could store in the dependencies annotation file so user can jump there to see more info.

We need to check how we choose to represent those annotations, but we could do something similar to scala nowarn annotation

Interface FunctionUsingAnnotation {
  // doc for using annotation
  fn using(
      // doc for preapprovedAssets
      preapprovedAssets: Bool,
      // doc for assetsInContract
      assetsInContract: Bool,
      // doc for payToContractOnly
      payToContractOnly: Bool,
      // doc for checkExternalCaller
      checkExternalCaller: Bool,
      // doc for updateFields
      updateFields: Bool,
      // doc for methodIndex
      methodIndex: U256
    ) -> ()
}

It has to compile otherwise ralph-lsp will complain.

[tdroxler]

Another proposition is to send a message to the user when querying those info to go to our current document website: https://docs.alephium.org/ralph/functions/#annotations