Tells the delegate to open a single file.
- macOS 10.0+
The application object associated with the delegate.
The name of the file to open.
true if the file was successfully opened or
false if it was not.
Sent directly by
the to the delegate. The method should open the file
true if the file is successfully opened, and
false otherwise. If the user started up the application by double-clicking a file, the delegate receives the
application(_: message before receiving
application is sent before