I tried DuckDuckGo but didn't like the search results either. I'have had the exact same problems with the coding error searches the author had. The results were mostly useless. Then I tried startpage.com and never went back.
We use doxygen + markdown for high-level documentation. This way you can edit the documentation in a text editor and put the markdown files in version control. And with graphviz and mscgen you can even create some standard graphs. The doxygen-generated html documentation is then put inside a wiki automatically.