Search query builder automatically wraps "Exact string" with double quotes

Created by: unknwon

On sourcegraph.com:

Redirects user to https://sourcegraph.com/search?q=%22open%28%22&patternType=literal.

It is somewhat funny that before we have literal search as default, https://github.com/sourcegraph/sourcegraph/issues/2383 was reported no double quotes as a bug, now it's a bug on the other side 😂