Properly escape `&` in injected live-reload script tag (#825)

"[…] `&` normally indicates the start of a character entity reference or
numeric character reference; writing it as `&` […] allows `&` to be
included in the content of an element or in the value of an attribute."

From: https://en.wikipedia.org/wiki/HTML#Character_and_entity_references

components/site/src/lib.rs

@@ -633,7 +633,7 @@ impl Site {
             return html.replace(
                 "</body>",
                 &format!(
-                    r#"<script src="/livereload.js?port={}&mindelay=10"></script></body>"#,
+                    r#"<script src="/livereload.js?port={}&amp;mindelay=10"></script></body>"#,
                     port
                 ),
             );

components/site/tests/site.rs

@@ -161,7 +161,7 @@ fn can_build_site_without_live_reload() {
     assert!(file_exists!(public, "nested_sass/scss.css"));
 
     // no live reload code
-    assert_eq!(file_contains!(public, "index.html", "/livereload.js?port=1112&mindelay=10"), false);
+    assert_eq!(file_contains!(public, "index.html", "/livereload.js?port=1112&mindelay=10"), false);
 
     // Both pages and sections are in the sitemap
     assert!(file_contains!(