docs(datasources/influxdb): Fix broken image link

Twas missing a leading `/`.

docs/sources/datasources/influxdb.md

@@ -118,7 +118,7 @@ SHOW TAG VALUES WITH KEY = "hostname"  WHERE region =~ /$region/
 
 > Always you `regex values` or `regex wildcard` for All format or multi select format.
 
-![](img/docs/influxdb/templating_simple_ex1.png)
+![](/img/docs/influxdb/templating_simple_ex1.png)
 
 ## Annotations
 Annotations allows you to overlay rich event information on top of graphs.