Adjust SFx docs for new config keys
@@ -9,7 +9,8 @@ This sink sends Veneur metrics to [SignalFx](https://signalfx.com/).
# Configuration
* `signalfx_api_key` to set the API key.
-* `signalfx_hostname` to adjust where metrics are sent. If you use a proxy or something in front of SignalFx's API this is the place!
+* `signalfx_endpoint_base` to adjust where metrics are sent. If you use a proxy or something in front of SignalFx's API this is the place! Do not add a path (i.e. `https://ingest.signalfx.com` is right!)
+* `signalfx_hostname_tag` to adjust the tag in which the hostname of this instance will be added. SignalFx doesn't have a first-class hostname field, so this tag handles that.
# TODO
