rustdoc search: fix cache invalidation error

ever since rust-lang#129430, two queries with an identical userQuery can
have different results.  fixed by caching on the original query,
not the case folded version.

src/librustdoc/html/static/js/search.js

@@ -3588,7 +3588,7 @@ async function showResults(results, go_to_first, filterCrates) {
  results.query = DocSearch.parseQuery(searchState.input.value);
  }
 
- currentResults = results.query.userQuery;
+ currentResults = results.query.original;
 
  const [ret_others, ret_in_args, ret_returned] = await Promise.all([
  addTab(results.others, results.query, true),
@@ -3719,7 +3719,7 @@ async function search(forced) {
  const query = DocSearch.parseQuery(searchState.input.value.trim());
  let filterCrates = getFilterCrates();
 
- if (!forced && query.userQuery === currentResults) {
+ if (!forced && query.original === currentResults) {
  if (query.userQuery.length > 0) {
  putBackSearch();
  }