Add MAKE_DIRECTORY and RESULT to file()

[petk]

I'm not sure if the current behavior is intentional and correct me if I'm wrong, but I think that according to other patterns this would be a bit more consistent: MAKE_DIRECTORY is a multi-value keyword, RESULT is a one-value keyword.

Similar to other multi-value keywords in other commands.

[BlankSpruce]

It seems that file(MAKE_DIRECTORY) change isn't present in CMake 3.31 release notes:
https://cmake.org/cmake/help/latest/release/3.31.html#commands
even though RESULT is marked as new in 3.31:
https://cmake.org/cmake/help/latest/command/file.html#make-directory

I'll try to check later in CMake's repo if this is meant to land in 3.31 (since it's still in release candidate state) and if it does then your interpretation of how it should be treated is correct.

[BlankSpruce]

Addendum: since all invocations in the form file(FIRST_ARGUMENT ...) are in some way just differently spelled out imaginary commands file_first_argument (like file(MAKE_DIRECTORY ...) === file_make_directory(...) I've treated the list of arguments as a not keyworded sequence of arguments unless there are "actual" other keywords like this new RESULT. If I recall correctly install also suffers from that with one of multiple signatures selected through FIRST_ARGUMENT.

[BlankSpruce]

It looks like accidental omission so I opened an issue in CMake's repo: https://gitlab.kitware.com/cmake/cmake/-/issues/26377
Once it's confirmed I'll merge your change along with missing install(PACKAGE_INFO) and then release 0.16.2.

[petk]

I've also opened a PR here to add the new RESULT option: https://gitlab.kitware.com/cmake/cmake/-/merge_requests/9904