Update json.cpp

Fix "Conversion from brace-enclosed initializer list to std::tuple is ambiguous."

src/json.cpp

@@ -167,7 +167,7 @@ namespace jjx::json {
                 if (auto [token, new_index, error] = lexer(raw_json, i); i != new_index) {
                     // Error while lexing, return early
                     if (error.length()) {
-                        return {{}, error};
+                        return std::make_tuple(std::vector<jjx::json::token>{}, error);
                     }
 
                     // Store reference to the original source
@@ -182,7 +182,7 @@ namespace jjx::json {
             if (found) {
                 continue;
             }
-            return {{}, format_error("Unable to lex", raw_json, i)};
+            return std::make_tuple(std::vector<jjx::json::token>{}, format_error("Unable to lex", raw_json, i));
         }
         return {tokens, ""};
     }
@@ -328,7 +328,7 @@ namespace jjx::json {
         auto [tokens, error] = json::lex(source);
         if (error.size())
         {
-            return {{}, error};
+            return std::make_tuple(jjx::json::value{}, error);
         }
 
         auto [ast, _, error1] = json::parse(tokens);