Auto merge of #25888 - ferjm:text.decoration.2020, r=nox

Partial text decoration support for layout 2020

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #25166
- [X] There are tests for these changes

components/layout_2020/flow/root.rs

@@ -104,6 +104,7 @@ fn construct_for_root_element<'dom>(
             ))],
         )
     } else {
+        let propagated_text_decoration_line = style.clone_text_decoration_line();
         (
             ContainsFloats::No,
             vec![ArcRefCell::new(BlockLevelBox::Independent(
@@ -114,6 +115,7 @@ fn construct_for_root_element<'dom>(
                     display_inside,
                     contents,
                     ContentSizesRequest::None,
+                    propagated_text_decoration_line,
                 ),
             ))],
         )