VE-635: Keyboard shortcut for source editor

https://wikia-inc.atlassian.net/browse/VE-635
I'm not convinced that it should be done this way... and yes, you are correct, this bit weird way of passing target was introduced couple months ago already: https://github.com/Wikia/app/commit/74f2d19426060a6dc6d83d766939e660d0250b7c
Let's discuss tmrw in person.