kernel: fixes socket.erl type spec

the type specs for socker.erl were improved in PR-8986, but they
introduced a bug by omitting one of the overloaded specs. this commit
fixes that, and adds a test to check for it

lib/dialyzer/test/small_SUITE_data/src/sock.erl

@@ -0,0 +1,17 @@
+-module(sock).
+
+-export([sendto/4]).
+
+family({_,_,_,_}) -> inet;
+family({_,_,_,_,_,_,_,_}) -> inet6.
+
+sendto(Socket, IP, Port, Data) ->
+    Dest = #{family => family(IP),
+             addr => IP,
+             port => Port},
+    case socket:sendto(Socket, Data, Dest, nowait) of
+        ok -> ok;
+        Other  ->
+            logger:debug("sendto(~p) failed with: ~p", [Dest, Other]),
+            ok
+    end.

lib/kernel/src/socket.erl

@@ -3763,7 +3763,9 @@ an explanation of `TimeoutOrHandle`.
 """.
 
 -spec sendto(Socket :: socket(), Data :: iodata(),
-             Dest :: sockaddr(), Flags :: list()) -> Result when
+             Dest :: sockaddr(), Flags | TimeoutOrHandle) -> Result when
+      TimeoutOrHandle :: dynamic(),
+      Flags :: list(),
       Result :: 'ok'
               | {'ok', RestData :: binary()}
               | {'error', Reason}