rustdoc's web frontend search does not allow searching for paths

[emberian]

For example, if you try to search for File::open it will say nothing found.

[eastwood]

Requires significant re-factoring to search completely based on the index paths. For example searching for "File::" in this fix will return no results. Still need to search completely based on path (rather than name's + types) to completely fix. Will continue to work this