Rollup merge of rust-lang#59992 - QuietMisdreavus:static-settings-path, r=GuillaumeGomez

rustdoc: use --static-root-path for settings.js

At the time i was writing rust-lang/docs.rs#332, i noticed that the `settings.js` file that was being loaded was not being loaded from the `--static-root-path`. This PR fixes that so that users on docs.rs can effectively cache this file.

Author: Centril

Diff for: src/librustdoc/html/render.rs

@@ -2113,7 +2113,8 @@ impl Context {
                  &final_file);
 
         // Generating settings page.
-        let settings = Settings::new("./", &self.shared.resource_suffix);
+        let settings = Settings::new(self.shared.static_root_path.deref().unwrap_or("./"),
+                                     &self.shared.resource_suffix);
         page.title = "Rustdoc settings";
         page.description = "Settings of Rustdoc";
         page.root_path = "./";

Diff for: src/test/rustdoc/static-root-path.rs

@@ -12,3 +12,7 @@ pub struct SomeStruct;
 // @!matches - '"\.\./\.\./source-script\.js"'
 // @matches - '"\.\./\.\./source-files.js"'
 // @!matches - '"/cache/source-files\.js"'
+
+// @has settings.html
+// @matches - '/cache/settings\.js'
+// @!matches - '\./settings\.js'