LibWeb: Parse CSS timeline-scope property

Author: https://github.com/Calme1709
Commit: https://github.com/LadybirdBrowser/ladybird/commit/046dfdd1923
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/7884
Reviewed-by: https://github.com/gmta ✅

Tests/LibWeb/Text/expected/css/CSSStyleDeclaration-has-indexed-property-getter.txt

@@ -277,6 +277,7 @@ All properties associated with getComputedStyle(document.body):
     "text-decoration-style",
     "text-decoration-thickness",
     "text-overflow",
+    "timeline-scope",
     "top",
     "touch-action",
     "transform",

Tests/LibWeb/Text/expected/css/CSSStyleProperties-all-supported-properties-and-default-values.txt

@@ -780,6 +780,8 @@ All supported properties and their default values exposed from CSSStylePropertie
 'text-wrap-mode': 'wrap'
 'textWrapStyle': 'auto'
 'text-wrap-style': 'auto'
+'timelineScope': 'none'
+'timeline-scope': 'none'
 'top': 'auto'
 'touchAction': 'auto'
 'touch-action': 'auto'

Tests/LibWeb/Text/expected/css/getComputedStyle-print-all.txt

@@ -275,6 +275,7 @@ text-decoration-color: rgb(0, 0, 0)
 text-decoration-style: solid
 text-decoration-thickness: auto
 text-overflow: clip
+timeline-scope: none
 top: auto
 touch-action: auto
 transform: none