Update highlight.js examples to new, preferred, calling convention. See https://github.com/highlightjs/highlight.js/issues/2277

README.md

@@ -152,7 +152,7 @@ var md = require('markdown-it')({
   highlight: function (str, lang) {
     if (lang && hljs.getLanguage(lang)) {
       try {
-        return hljs.highlight(lang, str).value;
+        return hljs.highlight(str, { language: lang).value;
       } catch (__) {}
     }
 
@@ -172,7 +172,7 @@ var md = require('markdown-it')({
     if (lang && hljs.getLanguage(lang)) {
       try {
         return '<pre class="hljs"><code>' +
-               hljs.highlight(lang, str, true).value +
+               hljs.highlight(str, { language: lang, ignoreIllegals: true).value +
                '</code></pre>';
       } catch (__) {}
     }