Update SUPPORT.md (#19383)

Clarified how to get support, added link to official documentation

SUPPORT.md

@@ -1,9 +1,10 @@
-Need help or support?
+# Get Grafana help
 ------------------
+First, check the official [Grafana documentation](https://grafana.com/docs/).
 
- **Please note:**
-- Only submit issues for bug reports, feature requests or enhancements.
-- Grafana project uses GitHub mainly for tracking bugs and feature requests.
-- Asking a question by opening an issue will directly result in issue being closed.
+If you require further help or support then ask a question in the [Grafana community site](https://community.grafana.com/) or [Grafana Slack](http://slack.raintank.io/). You can also search the community site for previously answered questions, in case someone already had your problem and got help.
 
-If you require help or support then ask a question and/or find existing questions/answers in the [Grafana community site](https://community.grafana.com/).
+ **Please note:**
+- The Grafana project uses GitHub mainly for tracking bugs and feature requests.
+- Do not open an issue just to ask a question. The issue will be closed immediately.
+- Only submit issues for bug reports, feature requests, or enhancements.