update elements and fix some bugs

lib/src/prism/plugins/remove-initial-line-feed/prism-remove-initial-line-feed.js

+(function() {
+
+if (typeof self === 'undefined' || !self.Prism || !self.document) {
+        return;
+}
+
+Prism.hooks.add('before-highlight', function (env) {
+        if (env.code) {
+                var pre = env.element.parentNode;
+                var clsReg = /\s*\bkeep-initial-line-feed\b\s*/;
+                if (
+                        pre && pre.nodeName.toLowerCase() === 'pre' &&
+                        // Apply only if nor the <pre> or the <code> have the class
+                        (!clsReg.test(pre.className) && !clsReg.test(env.element.className))
+                ) {
+                        env.code = env.code.replace(/^(?:\r?\n|\r)/, '');
+                }
+        }
+});
+
+}());