Those are "Developer" items:
I can disable it in System Preferences (16):
However, I've read that some people can't disable Developer as they don't have the option on forums and what not. I do have an iCloud beta installed, so maybe the public release of Lion doesn't have that option, I'm not sure. I can eliminate all my .m and .h files from popping up.
If you don't have the GUI:
Navigate to com.apple.spotlight.plist (~/Library/Preferences) (You may need a file revealing app for this, like this which I wrote, teehee), open with a text editor, and add right before the
If you already have a key value named "SOURCE", replace
<false/>. It's probably near the bottom.