🔥 remove example for deprecated code

docs/examples/iterator_wrapper.cpp

@@ -1,29 +0,0 @@
-#include <iostream>
-#include <nlohmann/json.hpp>
-
-using json = nlohmann::json;
-
-int main()
-{
-    // create JSON values
-    json j_object = {{"one", 1}, {"two", 2}};
-    json j_array = {1, 2, 4, 8, 16};
-
-    //////////////////////////////////////////////////////////////////////////
-    // The static function iterator_wrapper was deprecated in version 3.1.0
-    // and will be removed in version 4.0.0. Please replace all occurrences
-    // of iterator_wrapper(j) with j.items().
-    //////////////////////////////////////////////////////////////////////////
-
-    // example for an object
-    for (auto& x : json::iterator_wrapper(j_object))
-    {
-        std::cout << "key: " << x.key() << ", value: " << x.value() << '\n';
-    }
-
-    // example for an array
-    for (auto& x : json::iterator_wrapper(j_array))
-    {
-        std::cout << "key: " << x.key() << ", value: " << x.value() << '\n';
-    }
-}

docs/examples/iterator_wrapper.output

@@ -1,7 +0,0 @@
-key: one, value: 1
-key: two, value: 2
-key: 0, value: 1
-key: 1, value: 2
-key: 2, value: 4
-key: 3, value: 8
-key: 4, value: 16