Abuses the Custom Editor API to associate filetypes of your choice with the default program defined by your OS.
With respect to sandcastle's Open, which I borrowed the file-opening code from.
To my knowledge, all the other extensions like this are adding commands or context menu items. Because this one pretends to be a custom editor, you can set it as the primary handler of a filetype, meaning all you have to do from then on is click the file and it'll open in the external editor.
From the Explorer view, right-click a file, Open With..., System Editor.
From that Open With dialog, you can also click "Configure default editor for ___" to always open files with the system editor.
Or edit the setting manually in your settings.json or the UI:
"workbench.editorAssociations": {
...
"*.docx": "open-with-system"
},TODO: Record GIFs
This took me like an hour to make, there's probably something.
Only tested on Windows.
Initial release!