Use ListInstance typedef in more places

Change-Id: Ic41218a1e09f76d7455816163d9b3ca24b0b94ca
diff --git a/src/ast_handlers.hpp b/src/ast_handlers.hpp
index b9d7a9d..870d255 100644
--- a/src/ast_handlers.hpp
+++ b/src/ast_handlers.hpp
@@ -306,7 +306,7 @@
 
 struct trailingSlash_class;
 
-std::set<Completion> generateMissingKeyCompletionSet(std::set<std::string> keysNeeded, std::map<std::string, leaf_data_> currentSet);
+std::set<Completion> generateMissingKeyCompletionSet(std::set<std::string> keysNeeded, ListInstance currentSet);
 
 struct createKeySuggestions_class {
     template <typename T, typename Iterator, typename Context>