Add display-4.vim

https://www.w3.org/TR/2024/WD-css-display-4-20241219/

Author: hail2u

after/syntax/css/display-4.vim

@@ -0,0 +1,2 @@
+syn keyword cssFontProp contained reading-flow
+syn keyword cssFontAttr contained flex-visual flex-flow grid-rows grid-columns

test/test.css

@@ -339,6 +339,14 @@
   display: run-in;
 }
 
+.display-4 {
+	reading-flow: auto;
+	display: flex-visual;
+	display: flex-flow;
+	display: grid-rows;
+	display: grid-columns;
+}
+
 .easing-1 {
   display: auto;
 }