Reorganize directories (#3462)

* 🚚 move files
* 🚚 rename doc folder to docs
* 🚚 rename test folder to tests

docs/examples/basic_json__InputIt_InputIt.cpp

@@ -0,0 +1,32 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // create JSON values
+    json j_array = {"alpha", "bravo", "charly", "delta", "easy"};
+    json j_number = 42;
+    json j_object = {{"one", "eins"}, {"two", "zwei"}};
+
+    // create copies using iterators
+    json j_array_range(j_array.begin() + 1, j_array.end() - 2);
+    json j_number_range(j_number.begin(), j_number.end());
+    json j_object_range(j_object.begin(), j_object.find("two"));
+
+    // serialize the values
+    std::cout << j_array_range << '\n';
+    std::cout << j_number_range << '\n';
+    std::cout << j_object_range << '\n';
+
+    // example for an exception
+    try
+    {
+        json j_invalid(j_number.begin() + 1, j_number.end());
+    }
+    catch (json::invalid_iterator& e)
+    {
+        std::cout << e.what() << '\n';
+    }
+}