Fix typo (#12041)

joth76 · web-flow · commit 35f4cdd1a026 · 2020-02-10T20:18:46.000+01:00
There are 3 options listed, not 2.
diff --git a/source/_docs/installation/synology.markdown b/source/_docs/installation/synology.markdown
@@ -10,7 +10,7 @@ Synology only provide Python 3.5.1, which is not compatible with Home Assistant
 
 </div>
 
-There are 2 alternatives, when using Home Assistant on Synology NAS:
+There are 3 alternatives, when using Home Assistant on Synology NAS:
 1. using Docker
 2. directly running on DSM
 3. using Hass.io in a VM (if you have an Intel based Synology)
