Add and improve golang snippets

* Basically none of the functions are ending at the functions closing brackets. I've add to all statements and endpoint.
* The snippet for struct had a wrong number.
* The printf and sprintf should rename after % not directly %s. Otherwise everytime the user has to type % again and again, which kinda doesn't make sense for these functions.
* Add log.Printf and log.Println for adding quickly log prints, which imho is very useful for debugging with print statements.