* Add C++ header for cpp-pistache-server to fix breaking CMake build of generated code.
* Sort includes of system C++ headers for cpp-pistache-server.
* Add samples generated from fixing bug #19683.
- Handling `std::set` in cpp-restdsk
- Member variables using `std:set` added to `Pet` in cpp-restsdk 3.0 Petstore sample
[cpp-pistache-server] taking into account a remark on this issue about cpp-pistache-server and its set management
- Switching `std::vector` to `std::set` for openapi set type in cpp-pistache-server
When components/schema/<object> reference other objects, validate() was
getting called on the referenced objects with no arguments. The return
value was void, but checked as if it was a boolean value.
