One thing that would really help and guarantee that I use DDG over Google for this kind of search would be to keep your links to documentation pages up to date, or at least give an easy selection.
Google is really bad at this. For instance, most links to pages in the Apache docs on Google are for 1.x, which all have a big header that says "This is deprecated, use 2.x". I use 2.x so the 1.x links are annoying, and it would be difficult if Apache didn't provide a link right there.
Another example is PostgreSQL. Google has _always_ been bad at providing up-to-date links to the PgSQL manual, even now it's usually 8.0-8.2 results that come up (the current version is 9.0.x). It's annoying because Postgres doesn't have an easy jump-to-current link like Apache, so I have to go up to the address bar, delete the older version number, and replace it with my current version number or the word "current", which always points to the latest.
I know it would be hard to do this for general results, but for official documentation it shouldn't be too difficult since the URLs usually contain the version number in a reliable format.
So, if I searched for "postgresql grant", as an example, I would like recent results to come up, or at least an easy way to choose which version of the documentation to use before I clicked out. If I have to write "postgresql grant 9.0" or something similar that would be OK too. Google does poorly at this even when you specify the version number you want as just shown.