Add overflow-5.vim

https://www.w3.org/TR/2024/WD-css-overflow-5-20241217/

Author: hail2u

after/syntax/css/overflow-5.vim

@@ -0,0 +1,2 @@
+syn keyword cssFontProp contained scroll-marker-group
+syn keyword cssPseudoClassId contained scroll-marker-group scroll-marker target-current

test/test.css

@@ -752,6 +752,12 @@ mask {
   display: fragments;
 }
 
+.overflow-5::scroll-marker-group,
+.overflow-5::scroll-marker,
+.overflow-5:target-current {
+	sroll-marker-group: auto;
+}
+
 .overscroll-1 {
   overscroll-behavior: auto;
   overscroll-behavior-block: auto;