Output entry attributes in `ligo info list-declarations --only-ep`

The new entry syntax doesn't work in ligo info list-declarations --only-ep. Consider this example JsLIGO contract:

namespace IncDec {
  type storage = int;
  type ret = [list<operation>, storage];
  // Three entrypoints

  // @entry
  const increment = (delta: int, store: storage): ret =>
    [list([]), store + delta];
  // @entry
  const decrement = (delta: int, store: storage): ret =>
    [list([]), store - delta];
  // @entry
  const reset = (_: unit, _: storage): ret => [list([]), 0]
};

/* Tests for main access point */

const test_initial_storage =
  (
    () => {
      let initial_storage = 42;
      let [taddr, _, _] =
        Test.originate_module(contract_of (IncDec), initial_storage, 0 as tez);
      return assert(Test.get_storage(taddr) == initial_storage)
    }
  )();

const test_increment =
  (
    () => {
      let initial_storage = 42;
      let [taddr, _, _] =
        Test.originate_module(contract_of (IncDec), initial_storage, 0 as tez);
      let contr = Test.to_contract(taddr);
      let _ = Test.transfer_to_contract_exn(contr, (Increment(1)), 1 as mutez);
      return assert(Test.get_storage(taddr) == initial_storage + 1)
    }
  )();

Running ligo info list-declarations --only-ep yields no declarations. This prevents some things in the LSP from working, such as compiling contracts. This will also be interesting for the debugger, which uses this command as well.

Acceptance criteria

• ligo info list-declarations --only-ep can work with the new entry attributes.
• Tests added.