Bind numpad_add and numpad_subtract as alternates for zoom commands

[tkelman]

• VSCode Version: 1.6.0-insider
  
• OS Version: Windows 10 Insider build 14915

Steps to Reproduce:

1. Using a keyboard that has a keypad (large laptop in my case), try zooming with ctrl and the keypad plus/minus. This works in Firefox and many other applications as an alternative to the -/= keys between 0 and backspace on a US keyboard.
2. I think this should be doable with custom keybindings ala https://code.visualstudio.com/docs/customization/keybindings but I haven't quite managed to get that working. This might be a standard and useful enough binding for these keys that it would be worth making default though? Opinions?

edit: #983 is somewhat related

[bpasero]

This feature request will not be considered in the next 6-12 months roadmap and as such will be closed to keep the number of issues we have to maintain actionable. Thanks for understanding and happy coding!