Libraries ranked higher than classes in search results

[InMatrix]

Some users found it surprising that a library is ranked higher than classes of the same name. Here's an example:

It makes sense that developers are more likely to be looking up classes and methods than libraries. @srawlins pointed out it's done at https://github.com/dart-lang/dartdoc/blob/main/lib/src/search.dart#L176. Maybe we can revisit this heuristic.