script: Tell devtools whether a node is displayed or not (#38575)

Doing so makes the devtools inspector display the nodes in gray, as it
is the case in firefox.
The relevant node parameter already exists but is hardcoded.

Before:
<img width="1108" height="408" alt="image"
src="https://github.com/user-attachments/assets/4a442fc9-92db-4a97-9e70-3b02f994a9d1"
/>


After:
<img width="1169" height="404" alt="image"
src="https://github.com/user-attachments/assets/ec1674a4-c025-4ceb-93c8-0cc3f695ddc7"
/>


Testing: We don't have tests for the devtools inspector.

Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>

components/script/dom/node.rs

@@ -1320,6 +1320,10 @@ impl Node {
             is_shadow_host,
             shadow_root_mode,
             display,
+            // It is not entirely clear when this should be set to false.
+            // Firefox considers nodes with "display: contents" to be displayed.
+            // The doctype node is displayed despite being `display: none`.
+            is_displayed: !self.is_display_none() || self.is::<DocumentType>(),
             doctype_name: self
                 .downcast::<DocumentType>()
                 .map(DocumentType::name)