Only emit specs related to the current doc entry for erlang functions

Avoid loading and parsing typespecs for erlang functions with documentation
Improves doc and spec rendering in documentation and signature providers
Fixes #252

lib/elixir_sense/core/introspection.ex

@@ -1189,6 +1189,12 @@ defmodule ElixirSense.Core.Introspection do
     []
   end
 
+  # erlang docs have signature included in metadata
+  def get_spec_as_string(_module, _function, _arity, :function, %{signature: signature}) do
+    [{:attribute, _, :spec, spec}] = signature
+    spec |> spec_to_string()
+  end
+
   def get_spec_as_string(_module, function, arity, :macro, %{implementing: behaviour}) do
     TypeInfo.get_callback(behaviour, :"MACRO-#{function}", arity + 1) |> spec_to_string()
   end
@@ -1291,6 +1297,11 @@ defmodule ElixirSense.Core.Introspection do
     end)
   end
 
+  def spec_to_string({{_module, name, arity}, specs}) when is_atom(name) and is_integer(arity) do
+    # spec with module - transform it to moduleless form
+    spec_to_string({{name, arity}, specs})
+  end
+
   @spec actual_module(
           nil | module,
           [{module, module}],