Because `Strings OS_OSX::get_name() const` now returns "macOS" (15a9f94346)
The C# GodotTools were still using "OSX" as identifier a few things were borken (e.g. dotnet/msbuild detection).
This will be used for communicating between the Godot editor and external IDEs/editors, for things like opening files, triggering hot-reload and running the game with a debugger attached.