Add css3-syntax.vim

See also: http://www.w3.org/TR/css3-syntax/

test/test.css

@@ -553,6 +553,10 @@
   display: reduced;
 }
 
+.syntax {
+  display: auto;
+}
+
 .text-3 {
   hyphens: manual;
   line-break: loose;

test/test.html

@@ -610,6 +610,11 @@
 }
 </style>
 <style>
+.syntax {
+  display: auto;
+}
+</style>
+<style>
 .text-3 {
   hyphens: manual;
   line-break: loose;