Add an insert overload function (#1110)

diff --git a/include/json/value.h b/include/json/value.h
index 0c98441..c4b29b9 100644
--- a/include/json/value.h
+++ b/include/json/value.h
@@ -445,8 +445,10 @@
   /// Equivalent to jsonvalue[jsonvalue.size()] = value;
   Value& append(const Value& value);
   Value& append(Value&& value);
+
   /// \brief Insert value in array at specific index
-  bool insert(ArrayIndex index, Value newValue);
+  bool insert(ArrayIndex index, const Value& newValue);
+  bool insert(ArrayIndex index, Value&& newValue);
 
   /// Access an object value by name, create a null member if it does not exist.
   /// \note Because of our implementation, keys are limited to 2^30 -1 chars.