Fix default Go code

static/index.html

@@ -155,11 +155,14 @@ pub fn square(num: i32) -> i32 {
 }</div>
         <div class="template lang go">// Type your code here, or load an example.
 // Your function name should start with a capital letter.
-package main;
+package main
 
 func Square(x int) int {
-  return x * x
-}</div>
+	return x * x
+}
+
+func main() {}
+  </div>
         <div class="template lang d">// Type your code here, or load an example.</div>
 
         <map name="ghm">