Completed patch searching for rust docs
Made temporary changes to include multiple keywords in rustdoc search

Implemented search based on multiple keywords

Added some commenting and house cleaning

Added path searching to rustdoc
auto merge of #11438 : b1nd/rust/rust-doc, r=alexcrichton

cc @cmr

Temporary change to issue #10535. 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