switch to a Document trait and introduce Script/Head/Style/Meta components (#2635)

* switch to a Document trait and introduce Script/Head/Style/Meta components

* Fix desktop title

* Insert special elements into the head during the inital SSR render

* Make all head component attributes optional

* hydrate head elements

* improve the server streaming head warning

* Document fullstack head hydration approach

* deduplicate head elements by href

* move Link into head::Link

* document head components

* add meta and title examples

* Fix a few doc examples

* fix formatting

* Add title to playwright tests

* serde is optional on web, but it is enabled by hydrate

* remove leftover console log

packages/html/src/elements.rs

@@ -655,6 +655,11 @@ builder_constructors! {
         title: String DEFAULT, // FIXME
         r#type: Mime "type",
         integrity: String DEFAULT,
+        disabled: Bool DEFAULT,
+        referrerpolicy: ReferrerPolicy DEFAULT,
+        fetchpriority: FetchPriority DEFAULT,
+        blocking: Blocking DEFAULT,
+        r#as: As "as",
     };
 
     /// Build a
@@ -665,6 +670,7 @@ builder_constructors! {
         content: String DEFAULT,
         http_equiv: String "http-equiv",
         name: Metadata DEFAULT,
+        property: Metadata DEFAULT,
     };
 
     /// Build a
@@ -1261,6 +1267,8 @@ builder_constructors! {
         nonce: Nonce DEFAULT,
         src: Uri DEFAULT,
         text: String DEFAULT,
+        fetchpriority: String DEFAULT,
+        referrerpolicy: String DEFAULT,
 
         r#async: Bool "async",
         r#type: String "type", // TODO could be an enum