Updated Inject JavaScript Code (markdown)

Inject-JavaScript-Code.md

@@ -22,4 +22,5 @@ This can be done with following snippet:
 
 var ss = document.createElement("style");
 ss.type = "text/css"; ss.innerHTML = css;
-document.getElementsByTagName("head")[0].appendChild(ss); })();```
+document.getElementsByTagName("head")[0].appendChild(ss); })();
+```