Interesting idea. Also, DuckDuckGo can do the same:

  https://duckduckgo.com/?q=%21ducky+inurl%3Aen.wikipedia+%s

I also use Google's "I'm feeling lucky" as my default search so I can type e.g. "mdn array" to look up the JS array docs quickly. I used to use DuckDuckGo's version but the results were unfortunately too inaccurate.