Add lang str remainder to highlight callback

``` javascript {line-numbers=5 highlight=14-17}
    test
    ```

This markup now calls `highlight` like this:

    require('markdown-it')({
      highlight(code, lang, attrs) {
        assert(code === 'test')
        assert(lang === 'javascript')
        assert(attrs === '{line-numbers=5 highlight=14-17}')
      }
    })

close https://github.com/markdown-it/markdown-it/issues/626
close https://github.com/markdown-it/markdown-it/pull/706

lib/renderer.js

@@ -40,14 +40,17 @@ default_rules.fence = function (tokens, idx, options, env, slf) {
   var token = tokens[idx],
       info = token.info ? unescapeAll(token.info).trim() : '',
       langName = '',
-      highlighted, i, tmpAttrs, tmpToken;
+      langAttrs = '',
+      highlighted, i, arr, tmpAttrs, tmpToken;
 
   if (info) {
-    langName = info.split(/\s+/g)[0];
+    arr = info.split(/(\s+)/g);
+    langName = arr[0];
+    langAttrs = arr.slice(2).join('');
   }
 
   if (options.highlight) {
-    highlighted = options.highlight(token.content, langName) || escapeHtml(token.content);
+    highlighted = options.highlight(token.content, langName, langAttrs) || escapeHtml(token.content);
   } else {
     highlighted = escapeHtml(token.content);
   }

test/misc.js

@@ -62,6 +62,18 @@ describe('API', function () {
     assert.strictEqual(md.render('```\n&\n```'), '<pre><code>&amp;\n</code></pre>\n');
   });
 
+  it('highlight arguments', function () {
+    var md = markdownit({
+      highlight: function (str, lang, attrs) {
+        assert.strictEqual(lang, 'a');
+        assert.strictEqual(attrs, 'b  c  d');
+        return '<pre><code>==' + str + '==</code></pre>';
+      }
+    });
+
+    assert.strictEqual(md.render('``` a  b  c  d \nhl\n```'), '<pre><code>==hl\n==</code></pre>\n');
+  });
+
   it('force hardbreaks', function () {
     var md = markdownit({ breaks: true });