Move search JS into search-index.js

Export a few variables and functions into the global scope because they
are needed both by main.js and search-index.js.

src/librustdoc/html/render/write_shared.rs

@@ -408,9 +408,8 @@ pub(super) fn write_shared(
     // with rustdoc running in parallel.
     all_indexes.sort();
     write_crate("search-index.js", &|| {
-        let mut v = String::from("var searchIndex = JSON.parse('{\\\n");
-        v.push_str(&all_indexes.join(",\\\n"));
-        v.push_str("\\\n}');\ninitSearch(searchIndex);");
+        let v = static_files::SEARCH_JS
+            .replace(r#""SEARCH_INDEX_PLACEHOLDER": {}"#, &all_indexes.join(",\\\n"));
         Ok(v.into_bytes())
     })?;
 

src/librustdoc/html/static_files.rs

@@ -24,6 +24,10 @@ crate static NORMALIZE_CSS: &str = include_str!("static/normalize.css");
 /// including search behavior and docblock folding, among others.
 crate static MAIN_JS: &str = include_str!("static/main.js");
 
+/// The file contents of `search-index.js`, which contains the search behavior,
+/// and into which is interpolated the search index.
+crate static SEARCH_JS: &str = include_str!("static/search.js");
+
 /// The file contents of `settings.js`, which contains the JavaScript used to handle the settings
 /// page.
 crate static SETTINGS_JS: &str = include_str!("static/settings.js");