Fix dialyzer warnings.

src/syn_backbone.erl

@@ -345,7 +345,7 @@ i_find_by_pid(Pid) ->
         _ -> undefined
     end.
 
--spec return_if_on_connected_node(Process :: #syn_processes_table{}) -> boolean().
+-spec return_if_on_connected_node(Process :: #syn_processes_table{}) -> Process :: #syn_processes_table{} | undefined.
 return_if_on_connected_node(Process) ->
     case lists:member(Process#syn_processes_table.node, [node() | nodes()]) of
         true -> Process;

src/syn_sup.erl

@@ -50,7 +50,7 @@ start_link() ->
 %% Callbacks
 %% ===================================================================
 -spec init([]) ->
-    {ok, {{supervisor:strategy(), non_neg_integer(), non_neg_integer()}, [supervisor:child_spec()]}}.
+    {ok, {{supervisor:strategy(), non_neg_integer(), pos_integer()}, [supervisor:child_spec()]}}.
 init([]) ->
     Children = [
         ?CHILD(syn_backbone, worker),