Update cmd + K to support Firefox & Windows

[danpastori]

Current Behavior

cmd + K search doesn't operate as expected in Firefox or on Windows machines

Expected Behavior

Pressing cmd + k to search should bring up the docs search

Steps To Reproduce

Press cmd + k to search

Environment

N/A

Anything else?

Problem
cmd + K in Firefox jumps to the search bar within the browser and not within Spin

Solution
https://github.com/jaywcjlove/hotkeys-js

Utilizing hotkeys.js can prevent the default commands from running scoping the cmd + k to Spin. We should also support ctrl + k for Windows machines