Correct links for Push interface (#1299)

Signed-off-by: Arthur Axel 'fREW' Schmidt <github@frew.co>

content/docs/instrumenting/pushing.md

@@ -19,7 +19,7 @@ makes it easy to instrument even shell scripts without a client library.
 [PushGateway](https://prometheus.github.io/client_java/io/prometheus/client/exporter/PushGateway.html)
 class.
 
- * For use from Go see the [Push](http://godoc.org/github.com/prometheus/client_golang/prometheus#Push) and [PushAdd](http://godoc.org/github.com/prometheus/client_golang/prometheus#PushAdd) functions.
+ * For use from Go see the [Push](https://godoc.org/github.com/prometheus/client_golang/prometheus/push#Pusher.Push) and [Add](https://godoc.org/github.com/prometheus/client_golang/prometheus/push#Pusher.Add) methods.
 
  * For use from Python see [Exporting to a Pushgateway](https://github.com/prometheus/client_python#exporting-to-a-pushgateway).