Update sizing-4.vim

https://www.w3.org/TR/2021/WD-css-sizing-4-20210520/

after/syntax/css/sizing-4.vim

@@ -1,2 +1,3 @@
 syn match cssFontProp contained "\<contain-intrinsic-size\>"
-syn match cssFontAttr contained "\<\fit-content\>"
+syn match cssFontProp contained "\<min-intrinsic-sizing\>"
+syn match cssFontAttr contained "\<zero-if-\(scroll\|extrinsic\)\>"

test/test.css

@@ -885,7 +885,10 @@ mask {
 
 .sizing-4 {
 	contain-intrinsic-size: auto;
+	min-intrinsic-sizing: auto;
 	display: fit-content;
+	display: zero-if-scroll;
+	display: zero-if-extrinsic;
 }
 
 .speech-1 {