Add cssom.vim

See also: http://www.w3.org/TR/cssom/

test/test.css

@@ -181,6 +181,10 @@
   display: smooth;
 }
 
+.cssom {
+  display: auto;
+}
+
 .display {
   box-suppress: flow;
   display: flow-root;

test/test.html

@@ -206,6 +206,11 @@
 }
 </style>
 <style>
+.cssom {
+  display: auto;
+}
+</style>
+<style>
 .display {
   box-suppress: flow;
   display: flow-root;