Remove other hard deprecations

Author: José Valim

lib/elixir/lib/code.ex

@@ -1121,7 +1121,7 @@ defmodule Code do
   longer available, and therefore this function always returns `nil`.
   Use `Code.fetch_docs/1` instead.
   """
-  @deprecated "Code.get_docs/2 always returns nil as its outdated documentation is no longer stored on BEAM files. Use Code.fetch_docs/1 instead"
+  @doc deprecated: "Code.get_docs/2 always returns nil as its outdated documentation is no longer stored on BEAM files. Use Code.fetch_docs/1 instead"
   @spec get_docs(module, :moduledoc | :docs | :callback_docs | :type_docs | :all) :: nil
   def get_docs(_module, _kind) do
     nil

lib/elixir/src/elixir_module.erl

@@ -331,7 +331,7 @@ warn_unused_attributes(File, DataSet, DataBag, PersistedAttrs) ->
   StoredAttrs = bag_lookup_element(DataBag, attributes, 2),
   %% This is the same list as in Module.put_attribute
   %% without moduledoc which are never warned on.
-  Attrs = [doc, typedoc, impl, deprecated | StoredAttrs -- PersistedAttrs],
+  Attrs = [doc, typedoc, impl, deprecated | StoredAttrs -- [since | PersistedAttrs]],
   Query = [{{Attr, '_', '$1'}, [{is_integer, '$1'}], [[Attr, '$1']]} || Attr <- Attrs],
   [elixir_errors:form_warn([{line, Line}], File, ?MODULE, {unused_attribute, Key})
    || [Key, Line] <- ets:select(DataSet, Query)].