Function showInFileManager
Show and select directory or file in OS file manager.
bool showInFileManager
(
string pathName
);
On Windows this shows file in File Exporer.
On macOS it reveals file in Finder.
On Freedesktop systems this function finds user preferred program that used to open directories.
If found file manager is known to this function, it uses file manager specific way to select file.
Otherwise it fallbacks to opening pathName if it's directory or parent directory of pathName if it's file.