Auto merge of #119001 - notriddle:notriddle/searchwords, r=GuillaumeGomez

rustdoc-search: remove parallel searchWords array

This might have made sense if the algorithm could use `searchWords` to skip having to look at `searchIndex`, but since it always does a substring check on both the stock word and the normalizedName, it doesn't seem to help performance anyway.

Profile: http://notriddle.com/rustdoc-html-demo-8/searchwords/index.html

Author: bors