Reorganize directories (#3462)

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

docs/examples/insert__range_object.output

@@ -0,0 +1,3 @@
+{"one":"eins","two":"zwei"}
+{"eleven":"elf","seventeen":"siebzehn"}
+{"eleven":"elf","one":"eins","seventeen":"siebzehn","two":"zwei"}