Change to remove support for ancient lang on code with spaces

Author: wooorm

lib/handlers/code.js

@@ -20,14 +20,11 @@
  */
 export function code(state, node) {
   const value = node.value ? node.value + '\n' : ''
-  // To do: next major, use `node.lang` w/o regex, the splitting’s been going
-  // on for years in remark now.
-  const lang = node.lang ? node.lang.match(/^[^ \t]+(?=[ \t]|$)/) : undefined
   /** @type {Properties} */
   const properties = {}
 
-  if (lang) {
-    properties.className = ['language-' + lang]
+  if (node.lang) {
+    properties.className = ['language-' + node.lang]
   }
 
   // Create `<code>`.