Add ScopeId::ROOT (#1398)

* add ScopeId::ROOT

* replace ScopeId(0) with ScopeId::ROOT

---------

Co-authored-by: Jani Mustonen <jani.mustonen@taitounited.fi>

packages/core/tests/attr_cleanup.rs

@@ -34,7 +34,7 @@ fn attrs_cycle() {
         ]
     );
 
-    dom.mark_dirty(ScopeId(0));
+    dom.mark_dirty(ScopeId::ROOT);
     assert_eq!(
         dom.render_immediate().santize().edits,
         [
@@ -56,7 +56,7 @@ fn attrs_cycle() {
         ]
     );
 
-    dom.mark_dirty(ScopeId(0));
+    dom.mark_dirty(ScopeId::ROOT);
     assert_eq!(
         dom.render_immediate().santize().edits,
         [
@@ -65,7 +65,7 @@ fn attrs_cycle() {
         ]
     );
 
-    dom.mark_dirty(ScopeId(0));
+    dom.mark_dirty(ScopeId::ROOT);
     assert_eq!(
         dom.render_immediate().santize().edits,
         [
@@ -88,7 +88,7 @@ fn attrs_cycle() {
     );
 
     // we take the node taken by attributes since we reused it
-    dom.mark_dirty(ScopeId(0));
+    dom.mark_dirty(ScopeId::ROOT);
     assert_eq!(
         dom.render_immediate().santize().edits,
         [