Press Cmd+Shift+L (Mac), or Ctrl+Shift+L (Windows)
The output (on a new line) will be: console.log('variable: ', variable);
Keyboard Shortcut
By default the keyboard shortcut is Cmd+Shift+L or Ctrl+Shift+L
If this shortcut interferes with another extension or system wide Shortcut, you may change it in the Keyboard Shortcuts Setting.
Press Cmd+P or Ctrl+P and type in Open Keyboard Shortcuts.
Search for Log Javascript Selection and click on the pen icon.
This is where you can enter any Shortcut you choose.