Visual Studio Code Shortcut Return to Single File View Editor Mode

You get the idea - you did CTRL + \ to go into split mode. Now, all you want to do is go OUT of this split mode.

Google gets you : View > Editor Layout > Single accomplishes this.

Now, shortcut please :)

CTRL + SHIFT + P for command palette and there "Preferences : Open Keyboard Shortcuts"

In this new tab, start typing "Editor single" and you strike gold.

Now, all you do is (how are you supposed to know this?) double click on this one and then it gives you a gorgeous dialog telling you to enter the desired shortcut sequence and then press enter.

Trust me, CTRL ALT \ and CTRL ALT SHIFT \ are taken. So settle for CTRL ALT /

If you want to go to the keybindings.JSON directly, you'll find its : 

{

"key": "ctrl+alt+/",

"command": "workbench.action.editorLayoutSingle"

}